The Wide World of Incremental Games
/Even before the incremental/idle/clicker genre became a “thing”, I’ve always been fascinated by games that let the player make progress without needing the player to actually be actively playing. Something about the idea of optimizing a process that you won’t actually be there for has always kind of enthralled me.
And yet, I’ve never really felt like Incremental games have ever managed to quite hit that level of the games I played in the past, that just happened to have these mechanics, but did not focus on them. I’ve played a lot of incremental games in my time, but it always seems like they fall just a little short of being actually “fun”.
These days they come in all shapes and sizes, each with their own strengths and weaknesses, and so I thought it might be fun to look back at some of the ones I have sunk a lot of time into. These are all titles that are purposefully a very stripped down experience, but perhaps by looking at what does and does not work, we can learn something about how to make an incremental game feel… well, more like an actual game. Or perhaps more interesting would be, how to work incremental elements into an already existing game.
(Note that this is not every clicker game I have played. There are many, many games in this genre today, because they are so easy to make. These are simply the ones that are probably the most well known, and/or that I have the best memory of, or I think are most worth talking about)
Adventure Capitalist
Adventure Capitalist is about as simple as it comes, even for this genre. There are a lot of bells and whistles, but the core loop essentially boils down to buying producers to generate money with which to buy more producers. At the beginning of the game the player must manually start each production cycle, which is actually a pretty fun mechanical challenge in juggling the different bars, as they all have different production speeds. This process is quickly automated away by purchasing “Manager” upgrades.
The game never really introduces anything new for the player to do with all the attention that is now free as a result of the automation. You can eventually start playing the same loop on multiple planets / seasonal events simultaneously, and of course you can “new game+”, as with many of these games, by purchasing angel investors, which will speed up your subsequent cycle. The actual management of all of these mechanics is very light however, and the game largely revolves around waiting until enough money has accrued to make your next major purchase.
Weaknesses
Automation comes at the cost of most player interaction. Once automation starts, there’s nothing new for the player to focus on
Individual purchases are basically meaningless. Only major upgrades and producer breakpoints really make a measurable difference
Values become so large that it becomes very difficult to distinguish them, even conceptually (how big is a Quatuorseptuagintillion vs a Treoctogintillion?)
Just in general, not a whole lot to do. It’s easy to come back every day for 30 seconds, but at that point is it even worth your time?
Strengths
Keeping efficiency up early game is fun - it’s a mechanical challenge to keep your producers going and minimize downtime
Strong presentation - everything is well themed, and the “capitalism” humor carries the game
Simplistic gameplay makes it very low friction to turn the game on every day and buy a few upgrades
A surprising amount of “personality” is worked into each producer type, just through things like cost, production time, upgrade breakpoints, etc
Each producer’s curve is balanced in a way that, they all get their time in the sun if you play long enough
With everything revolving around your money level, it becomes pretty easy to understand your progress
Cookie Clicker
Very similar to Adventure Capitalist, in that the core loop essentially revolves around making money (or in this case, cookies), and then spending it to increase your ability to make more. While Adventure Capitalist is more of an idle game, Cookie Clicker is, as the name implies, a clicker. This means the player can actively boost their progress speed at any time, but as is the norm, this quickly becomes a waste of time as the automatic producers far outstrip the clicking revenue. However the game does have the advantage of golden cookies. If the player sees one, they can click it to gain a large benefit, which often comes in the form of a massive boost to clicking revenue for a short time, which turns active play into the by-far most effective way to generate revenue.
One of the ways Cookie Clicker most sets itself apart from it’s peers (despite coming before basically all of them) is in it’s plethora of mini-games and subsystems. There are a lot of layers added onto the game as you progress, and they all give a little something extra to thnik about, usually accompanied with at least some amount of additional tasks for the player to execute. This does a decent job of giving the player more ways to actively engage with the game, as well as adding a bunch more ways to measure progress and generate goals, which matters a lot as you get into the realm of “I won’t hit my next goal for a year of farming”.
Weaknesses
Clicking pretty quickly becomes almost completely worthless
There is usually one kind of purchase that is clearly the most valuable, and every other producer/upgrade is pretty worthless
You can go a very long time in between purchases - progress tends to come in leaps and bounds
There are so many mechanics going on that, it’s easy to lose track and become a bit lost as to what your next move should be
Strengths
Very clean, very satisfying presentation. Themeing is subtle, but evolves over time, injecting a subtle narrative
Lots of different things to do, that are gradually added over time
Truly active play isn’t really reasonable, but golden cookies makes it a good game to have open in the background, checking back periodically to click the gold cookie
Ascension has a whole skill tree system, which adds a surprising amount of depth (at least, perceived depth) to a simple game
Soda Dungeon
This is a bit of a weird one, because at first impression, Soda Dungeon doesn’t even seem like an incremental game, and so it’s actually a pretty full-featured experience. Essentially, the player owns a tavern which attracts different types of adventurers. The player can recruit up to 5 of them, equip them with whatever gear the player has collected, and head into the dungeon to fight endless waves of turn based battles until they all die.
As you go you gain the ability to upgrade your tavern to attract different adventures, collect better gear, and can purchase sodas that upgrade each class’ stats. While the game starts off with lots of clicking abilities and has a little bit of strategy to it, eventually one gets to the point where going as far as you can go means clearing thousands, if not millions of waves of enemies. At this point the strategy shifts more towards creating a party that has longevity, and that will manage itself, which is interesting in it’s own way.
Weaknesses
Session length is waaaay too long. Going until you die can take days sometimes, at which point you aren’t likely interacting with the game at all, and you aren’t iterating your strategy
Long session length means you often won’t see where or why your team ended up dying, beating tough bosses, etc
Some strategies are a little too dominant- if you don’t find them, progress is slow, if you do, variety suffers a lot
It would be nice if there was a bit more variety. Setting up your team is fun, but it feels like they are always doing the same thing in roughly the same way
Strengths
Turn based battles are surprisingly deep for a game you’re not going to be looking at most of the time
Putting together a team is really satisfying. There are a lot of tools to play with, and one can build teams with many different goals
Despite the story being almost non-existent, it’s actually surprisingly interesting when you get to some of the later landmark dungeon floors
The mechanics all feel like they just work together. There isn’t a lot of complexity or confusion - a lot is accomplished with a little
A Dark Room
A Dark Room is another weird one, because in a lot of ways it almost isn’t an incremental game - it definitely doesn’t conform to what we tend to think of as an in idle or a clicker game. It’s just a very unique experience that evolves over time, and has incremental elements at it’s core. I think what I love about it the most is that, it’s got a narrative that is very strong using very little, and the feeling of pushing your little community forwards is very pervasive.
A Dark Room happens in stages. At the start, all you can do is stoke the fire. Quickly you get the ability to gather wood, and before long, other people start showing up that can be used as workers. You gain the ability to assign people to different jobs, gather different resource, start crafting things, and this is the strongest “incremental” phase of the game.
Eventually the game evolves again, and becomes an RPG where you can send a worker out to explore the world. You load them up with stuff so they can survive and fight against enemies, and while you run around scrounging for things, your little village is still producing in the background. Eventually you do beat the game, and this fact helps keep the game’s scope under control.
Weaknesses
There are a lot of random events that can happen in the early game that don’t feel like they have the weight or consequence that they should, mechanically or narratively
There are parts of the UI that are perhaps a bit too far on the simplistic side, as some mechanics I didn’t even know existed until my third time through the game
The RPG segment of the game is pretty repetitive. Unlocking it is a huge rush of “wow, this is a whole new game”, but it quickly becomes, another cave, another battle
Strenghts
Game evolves over time, so the gameplay doesn’t get stale, and the initial offering is not overwhelming (as you aren’t thrown into too many mechanics)
The narrative is very subtle, but adds a lot of depth to the game’s experience. Simple actions have a weight that they wouldn’t in other games
Managing your workers is a great feeling - it works like an idle game, but the resource management elements are significantly deeper than most games of this type
Once your village is up and running, you aren’t just left to idle for long periods of time, this is just the beginning of the RPG part of the game (but what your village is doing in the background is still important)
Very little of the game is ever actually “idle”. You can interact with the game for basically your entire playtime (but if you choose not to, you are still amassing useful resources)
Crank
Crank actually feels very similar to A Dark Room in a lot of ways. It features a very cryptic, but pervasive narrative, that prompts the player to kind of feel like they are exploring the unknown. Crank uses “power” similarly to how A Dark Room uses workers, and both of them feature a late-game stage wherein the goal shifts away from simply generating resources, to using those resources to explore their surroundings.
The focus of Crank, is on said crank. Turning it generates power, and everything kind of follows from there. What’s interesting about this is that, power is the game’s “main resource”, but it naturally depletes if the player doesn’t do anything, and so measuring your power use vs power generation becomes not just ideal, but required. Eventually one can create “crankbots” that will turn the crank for you, at which point the game shifts away from intensive micromanagement, towards a more contemplative stage of optimizing your resource production, and feeding power into the computer to do research, to try and figure out “what next”.
Weaknesses
Until the crank is properly automated, the early game is a huge grind. You make basically 0 progress if you aren’t manually turning the crank, and the game even pauses if the game window loses focus
The game can be a little too cryptic at times. Especially when you get to the exploration phase, you don’t really know what you are doing, or have the knowledge to form solid goals for yourself
The actual mechanics of how the crank, and in particular crankbots work, are kind of hard to grasp. You’re given a bunch of stats, but it’s hard to grasp how your actions affect them, and thus how the state of those stats should influence your actions
If you don’t find your way in the endgame pretty quickly, it’s really easy to become very overpowered, at which point it feels like you aren’t really using the exciting endgame mechanics, you’re just winning because you’re “overleveled”, so to speak
Strengths
Each of the game’s resources and mechanics are layered in such a way that, they serve multiple purposes as you progress. You’re interacting with the same stuff, but your experience with them evolves
I think the computer is secretly the star of the show. It paces out your tech progression, it drip feeds you narrative, gives you agency, etc.
The concept of power as compared to currency is kind of fun. Power is useless if you aren’t using it, so the focus clearly shifts away from “how much do you have”, in favour of “how quickly are you producing”, and to a lesser degree “how much can you hold”
For a game with this simple presentation, the feeling of discovery is vert strong. There’s just a lot of stuff here, and it’s all unlocked as you go, by your actions
Clicker Heroes
Honestly, I feel like Clicker Heroes doesn’t really have a whole lot on offer. It’s a fairly rudimentary clicker game. It really popularised the convention of having waves of enemies followed by a boss, and I think that this format works. Having the boss as a roadblock allows the game to be split into two distinct phases- you have the passive farming phase, and the active “pushing” phase. Pushing can be exciting after waiting for so long, and managing your cooldowns to further your current goal is mildly amusing. There is a reason this format has been adopted by so many games since Clicker Heroes hit the scene.
I most just wish there was more to the game, or at least that it became apparent sooner. The game’s core loop is very basic, and honestly just not that interesting. The “late game” seems like it has some interesting mechanics to reward players that have stuck with the game, but these mechanics take way too long to make themselves known. Before the late game, the gameplay is weak, the management elements are almost non-existent, and it really just feels like I’m playing a glorified progress quest - which is a criticism often levied against this genre, but Clicker Heroes is perhaps the only game I’ve felt that it was true of.
Weaknesses
Core loop is very simplistic - feels like going through the motions
Mechanics take a long time to be introduced- it’s easy to get the impression they don’t even exist
Everything about this game just feels like a 10 year old flash game
Strengths
Does a good job of supporting both passive and active play, between it’s different game “phases”, and some ability to create a “build” for yourself
There are a good number of mechanics in play to support players who stick around for the long haul
Merge Star
Merge Star is kind of an interesting oddity of a game in that, it looks and feels a lot like an incremental game, when in reality it really isn’t, so much as it is more of just a time waster. The concept of the game is that, your hero will fight an endless wave of enemies (each ending in a boss, much like Clicker Heroes), but he acts almost completely independently of your actions. All the player can do is outfit the hero with equipment. They have the ability to craft level 1 equipment rapidly, but to create more powerful equipment, they must be merged (ie. 2x lvl 1 swords makes a level 2 sword, 2x level 2 swords makes a level 3 sword, etc).
There are multitudes of upgrades and such to purchase on top of this with the gold you earn from idly killing monsters, but they don’t tend to do a ton for you. The meat of the game basically comes down to just merging equipment endlessly, until you have to wait before you can craft more level 1 gear. In other words, there is basically no idle play in this game, and your progress is dictated entirely by your active interaction with the game. The gameplay isn’t incredibly deep, but it feels a lot more like playing something like bejeweled than it does something like Clicker Heroes. There may be virtually no strategy, but at least matching like items together is slightly more engaging than just tapping.
Strengths
Essentially all of your progress is active, and so if your goal is to just kill time, you can essentially play for as long as you want and continue to make progress
Merging endlessly is a lot more engaging than clicking endlessly
The “crafting dungeon” creates a good way to enhance active farming for 30m at a time
Random “loot” integrates with the game well. Since loot is consumed to create better loot, even trash loot is cutting the time until your next upgrade. Good loot could cut the time in half suddenly!
This game handles large numbers pretty well, by quickly moving to a letter notation. It’s easy to tell that 1G gold is larger than 999F gold
Weaknesses
The merging gameplay and the combat gameplay feels pretty disconnected. It kind of feels like two mechanics just smooshed together. Merging can exist without the combat. Combat could have been fed by any other mechanic
Merging gets really boring eventually. The way you interact with the game doesn’t really change between the first hour and the hundredth. The only real changes come in the form of modifiers applied to the rewards you get for performing the same action as in every other dungeon
Time between upgrades become exponentially longer, and there is basically zero incremental progress between upgrades
One of only 2 games on this list that features no form of rebirth / ascension / whatever you want to call it. These mechanics exist for a reason!
Auto Battle
Auto Battle was, as far as I can tell, one of the first games of it’s ilk (which was then cloned and copied and iterated on a million times for years, as is the norm in mobile dev). Conceptually, you can basically just imagine your average full featured mobile RPG, and just imagine that the battles all take place endlessly and automatically. There are tons of modes and bells and whistles to tinker with, because those are kind of the point of the game.
It all works out pretty well if I’m honest. You have a good amount of ability to customize your character and build a battle strategy, even despite having no control once the battle starts. It’s strangely satisfying that your battles are taking place in the background while you micromanage your character’s skill and item setup. It’s basically like if you took Clicker Heroes, made it good, and then removed the clicking. There’s lots to do every day, and it’s really easy and low commitment to pick it up at any time, while also being a reasonably deep RPG.
Weaknesses
The presentation of the game is pretty behind the times. There is very little in terms of animations or visual flare. The game may be designed to play itself, but you have to look at it eventually
The game struggles a bit to scale up as the player progresses. Once you’ve been playing for a little bit, you stop getting new things to do, and getting a feel for your progression and what you should target as short term goals becomes a bit hazy
The game suffers a little bit because of it’s approach of being a social game where you measure yourself against other players, rather than a self-contained idle game focused on optimizing your individual experience (eg. No rebirth / ascension)
Strengths
Surprisingly deep RPG, for a game wherein you aren’t meant to look at the combat
You are really empowered to micromanage your character setup, get exactly the gear that you want, etc
It’s satisfying to be making constant progress without having to be actively playing. Being tied directly to RPG progression makes it more satisfying than “you got 9000 gold while offline!”
There’s a lot of potential things to to every day, so it never feels like by removing battle controls you are losing out on things to occupy your time with
Low commitment, short sessions are still valuable - you never really have to commit to taking the time to “spend your energy” like in most games
Idling to Rule the Gods
This is one of those weird games that kind of looks like trash, and yet, has a quite good approval rating on Steam. It has basically no obvious appear whatsoever. It’s kind of complicated, and even has a FAQ section built into the game client itself. It’s pretty solid as an Incremental game though, It’s like, the connoisseur’s Incremental game.
The concept here is that, you begin the game creating Shadow Clones, and those clones can then be put to work. You assign them to go training, fight monsters, build monuments, train your pets, etc. Each action has a certain form of return to your God, and when you are strong enough, you can fight other Gods to unlock other mechanics. As you grow stronger, your stat multipliers increase, and when you Rebirth, some amount of them carry over. If you Rebirth too early however, you may actually carry over a smaller multiplier than you had before, and so the game definitely wants you to progress at least as far as you did last time before Rebirthing.
One of my favourite things that this game does is that, over time, the amount of clones required to perform a specific task actually reduces. So maybe you need 10000 clones to kill the max number of Skeletons a second, but that number will gradually decrease, and soon enough you will be able to achieve the same productivity with just 1 clone. This gives a really great feeling of progress, as those 9999 other clones are now free to do new and interesting things!
Weaknesses
The presentation of this game is godawful. There is very little to look at, and what’s there is just really ugly
There are a lot of mechanics in this game, and most of them are just very poorly explained (even WITH the in-game FAQ). You get thrown into the deep-end at the start a bit
Even the way you interact with the interface is a bit obtuse. There are lots of buttons and toggles, and it’s not always clear what they even do (even after reading the tooltip)
All of the game’s bars are based on a cap, and ticks can’t roll over, which is pretty awkward at times (eg. if the cap is 100, there’s no difference between assigning 50 clones or 99, because either way it’s always 2 ticks per bar completion)
Strengths
You get a ton of clones, and a lot of ways of using them. This gives you a lot of control over what you are focusing on at any given time
The increasing efficacy of your clones means you want to adjust where your clones are allocated pretty frequently. The game may be idle, but there’s a lot of shifting resources around if you’re looking for that, and it allows semi-active play
The focus on making sure you get back to where you were as a minimum every rebirth means you’re always making measurable progress with an obvious goal, without feeling like you’re stuck in a farming loop
As lame as the graphics are, seeing your character get cool outfits and neat titles as you conquer more gods is actually surprisingly satisfying
Idle Champions of the Forgotten Realms
This game, horrendous name aside, is a really great example of the Clicker Heroes formula being brought to a much more appealing conclusion. The idea here is that you can recruit a number of different heroes for your party, and each has their own abilities and strengths. As many of 9 of them may be placed on your “grid”, and who goes where matters a lot, as most champions have abilities which will affect the performance of their nearby allies. One also has to worry about how much damage is coming in from enemies, and so the concept of tanks and healers exists here as well.
I think what really pushes this game over however, is the idea that the player can participate of a number of different Adventures. Each one has it’s own little quirk that will influence how you put your party together. Maybe there are a lot of beasts on one Adventure, whereas another one may have obstacles placed on your grid, restricting how many champions you may use and where you may place them. Not only do you have the ability to customize how you build each character and how they fit into your overall party, but the situations you face are something of a puzzle, so that you’re forced to switch things up.
Weaknesses
Clicking eventually becomes a fruitless endeavor, and there’s never really anything that replaces it as an active form of interacting with the game
This is basically a straight idle game, and when you get to the later stages of a map, you can go a long time between meaningful purchases. Get’s boring.
The amount of meta-progression in this game is kind of low, and so you find yourself starting back at square one frequently (basically every time you do an adventure you’ve not done before)e
Strengths
Lots of ability to customize your team, not just at the character level, but at the team level
The game creates a good variety of situations for you to solve using the aforementioned team customization
Everything is pretty easy to understand and interact with, which is an area that this game could have very easily fallen on it’s face
Swarm Simulator
Swarm Simulator is a pretty straightforward idle game that doesn’t really try to be more than it is. What’s there is pretty legit though (I really adore the low poly art style), and it has some kind of interesting ideas. So in this game, the main currency is Larva, rather than money. Larva are generated automatically over time, and can be spent to make either works, or warriors, each who have different goals.
Workers generate meat. Or more accurately, Drones generate meat, and each level of worker above Drones, will generate more of the worker below it. So for example, Queens generate Drones, but Nests generate Queens, and so on. This idea of producers which generate producers is kind of neat. Warriors on the other hand cost meat (and larva), and will generate territory, which is the most effective way to increase your overall speed of larva production.
There are ascensions and energy abilities and mutagen mutations and all that in play as well, but just in general, this is a simple game with a really tight loop that all feeds back into itself in slightly different ways than you may be used to seeing in similar games.
Weaknesses
There isn’t a lot to do here, so this game doesn’t really work so well as a time killer
You have to sacrifice lower level workers to make higher level ones, but they reuse similar icons frequently. How do you tell a little queen head apart from a greater queen? Or Nest from Hive?
There isn’t really much to build goals around in this game, it’s more of a “log in for 30 seconds, just to see how big the numbers can go” kind of game
Strengths
It’s simple, but solid. All the loops feed back to each other in a really easy way, and you don’t really have to understand how it all works to get what’s going on
The low poly art style is really vibrant and endearing
Producers creating producers is just a really cool concept to me. I’m an idle game nerd, leave me alone
There are little bars under the upgrades that indicate how long until you can purchase them, at your current rate. I really appreciate them, even if it’s not really typically important the way this game works
Idle Apocalypse
The idea of this mobile game is that, you are locked in eternal combat with a group of heroes. You must build a tower, with each floor either producing resources, or monsters. The monsters will automatically walk out the front door, and swat at the heroes until they are smote. This also generates resources, as your monsters each drop a unique resource when they die, and beating up the good guys also generates yet more resources.
The idea is to gradually build bigger and better creatures, and upgrade your Evil Idols. At any time the player may trigger an Apocalypse, during which all of your Idols will inflict as much damage as possible. Afterwards, the heroes will regenerate the world so that you restart from the beginning, and all of the souls you harvested during the Apocalypse will go towards making your next run faster and more fruitful.
I think the biggest way that this game differs from your average Incremental is that, the number of resources you are dealing with is pretty huge. Each floor of the tower typically has the potential to produce up to three different resources, and so you have to choose between them. Old resources will typically end up being required in the late game, and just in general, you are required to pay pretty close attention to what specific resources you currently need, and which you are currently producing (or if your stores will last you for a time). Keeping all your floors going without running dry on anything can be pretty challenging!
Weaknesses
With so much going on, it can be pretty easy to lose track of what your current progression goal actually even is. Sometimes just keeping your floors going isn’t actually pushing you forward at all
You have the ability to repeatedly use a damage spell on the heroes, but this does a pretty poor job of giving the player active progression. The spell is boring, only usable every 3s, and does very little damage
The game offers some cool events that are nice and self-contained little things which add a lot of value to any play session. BUT. They are active way too infrequently!
The identity of each floor could be a little stronger. Sometimes the game will tell me I get a component from a specific floor, and it can be hard to tell which one that even is
There is a long time between each Apocalypse, and there often isn’t a strong signal of when you should actually trigger it. So sometimes you end up grinding through a lot of really slow endgame stuff just to reach an arbitrary “I guess this works” point. Big commitment the player can’t make with a lot of confidence.
Strengths
The amount of resource management going on here can be pretty intense, as you will pretty quickly end up with like ~20 floors that are all generating and/or consuming one or more resources
There are several different generators you have to click repeatedly to power up, that introduce a kind of interesting semi-clicker element to the game. Makes it so that you have something to do other than just check your progress each session
There is a hard cap on how much offline time you will get credit for, which encourages you to check back at least 2-3 times a day, even if it’s only for like 20 seconds
One of the resources you need to unlock certain floors is only achieved by triggering Apocalypses, which forces the player to interact with that mechanic, preventing them from getting bogged down in a super slow late-game without the right tools
You can trade resources for skins for your monsters, which will carry over through the Apocalypse. Creates a neat visual sign of progress, but also forces an interesting decision between using them for something now, or something that will help you more over subsequent plays
In Conclusion
We’ve looked at a pretty broad spectrum of games here, most of which have very different goals, and hit different niches within the incremental genre, and so pulling specific learnings out of the analysis is a bit tricky. More than anything, I think I simply saw patterns insofar as the kind of games that I personally enjoy. It’s true of games in general that, what works for one game or one user may not necessarily work in every instance, and I think this just becomes especially noticeable when we look at incremental games, because the experience tends to be so stripped down, and so there isn’t really anything but the core loop to distract or entice you.
What I will say however, is that the biggest common thread among all of these titles, is that the standout aspects that make an incremental game good are basically the same as what makes any game good, incremental or otherwise. It should be understandable, engaging, deep but not complex, it should evolve over time, it should have good presentation and themeing, and so on.
And so, after examining these 12 games, I think my ideal incremental game would looks something like this:
Begins with a very straightforward experience. The player doesn’t have a lot to do, but it introduces the games primary mechanics and/or tone. This should be accompanied by strong narrative hooks. Investing heavily upfront when the payer has little else to focus on allows you to focus more on mechanics and usability later on, when the game’s context and tone have already been strongly established
Mechanics are dripfed to the player on a very tight schedule. This is something that will likely require quite a bit of balance work and testing. Top priority here is to give the player new things to do and think about just as they are getting the hang of the tools they already have. We don’t want to overwhelm the new player at the start, but we want to make sure they have mastered concepts before we move on. Ideally, whatever we introduce should re-conceptualize some or all of what they have learned so far, so that it’s just another layer in a familiar puzzle
I believe pretty strongly that the best incremental games have some element of worker allocation gameplay. It introduces an extra layer of management sim into the game, and simultaneously allows the player to feel like they are exercising agency (even if their available options are actually fairly slim).
Think very carefully about active progression, and when the player is likely to go idle. Consider when the player will run out of things to do, where in the process they may go idle, and how the game supports this. Some games are too tightly balanced, and going idle early on can completely wreck the progression curve. Other games have little or no way for the player to actively contribute to their progression once things are in motion, at which point they literally can’t engage with the game no matter how much they like it. There should be a sweet spot in between, wherein the player can meaningfully contribute to their progression, but is not punished if they choose not to do so.
Meaningful decisions should be frequent, and short and mid term goals abundant. It’s really easy in these games to find yourself farming for days at a time before anything exciting happens, and to just get lost in a sea of ever-balooning numerals. Some of them will have you going several days between actions that are actual meaningful, and that bar is just not that hard to beat. Remember that this is a game, the focus is on how the player can interact with it, not on how good it is at playing itself.
It should probably have an ending. It seems like pretty consistently, the games that are meant to end, are the ones that end up being the best. And I guess that isn’t especially surprising. These are the games that have the most ability to guide a player’s experience. Any progress-based game will go off the rails if left without content updates for long enough. If you leave it alone long enough, then maybe it becomes an interesting oddity that you poke at every now in then, but this is a game. We should derive value in meaningful interactions between the player and the software, not how big the number on the screen gets.