Why You Should Care About Idle Games — Mobile Free To Play

by Adam Telfer

Idle games are an exciting new genre that I expect to expand greatly in the coming years on mobile. Idle games, Clicker games, or “games that play themselves” is a baffling genre. Inexplicably these games are dominating many of the popular flash portals and shooting up the charts on mobile. Make it Rain by 337 Games, Tap Titans by Game Hive and now AdVenture Capitalist by Kongregate have all shown that this genre has a rightful place on the AppStore.

But why is this genre so popular? Why does this genre even exist? Why even discuss games that people don’t really play?

Idle games have risen on mobile because this is a genre that is perfect for modern mobile free-to-play design. The mechanics of idle games create perfect mobile sessions and drive strong long term retention.

What is an Idle Game?

Idle games, sometimes called Clicker or Incremental games, are games which are all about management of revenue streams. Similar to simulation games, their main differentiator is the focus on revenue growth decisions.

For some examples:

Cookie Clicker is the best example of an idle game. Each time you tap the cookie, you gain 1 cookie. You use cookies to purchase upgrades. Upgrades increase either the rate of tapping the cookie (now you get 2 cookies per click!) or increases the rate of cookies generated automatically (Grandmas will make 1 cookie per second). These automatic cookies are generated whether you are tapping or not. They are generated even if you’re away from the game.

On paper this sounds too simple to be fun. But try for yourself. The simple act of purchasing an upgrade always feels great. The growth curve is so fast it gets very addictive, very quickly.

Progress just for the sake of progress is fun. Even if it only means a virtual number increases faster.

Rate of resource generation is the core of the game. But an economy that inflates so quickly with a single currency has flaws. Very quickly, the game’s upgrade costs skyrocket. Starting off with nice low numbers the game quickly skyrockets into costs of trillions just a few sessions in. Most designers would cringe at this type of growth curve. What kind of player wants to worry about numbers in the trillions? In AdVenture Capitalist, your costs will eventually reach more than 1 Tretrigintillion (10 to the power of 102). Yet, players love this. Progress always feels good. Players playing for long enough to reach these ridiculous numbers feel like it is a real accomplishment.

As a result, Idle games have claimed 3 of the top 10 most played games on Kongregate (source: here). There are even Twitch channels dedicated to watching a computer play a game itself. Inexplicably, this genre has seen incredible growth.

Regardless of your stance of whether or not this is a “real” game genre, the mechanics in Idle games are perfectly realized for mobile. Idle games can teach mobile game designers a lot about creating a game that has strong session design. Idle games are so strong because:

1. It always feels good to come back.
2. Sessions naturally ease the player to leave
3. The mechanics ease the player from micro to macro gameplay

#1: It always feels good to come back

Many mobile games suffer gameplay mechanics that feel punishing on returning to the game after leaving for a few days.

In FarmVille: crops wither. If you do not come back to the game in time, your crops are worthless. In Clash of Clans: resources are stolen. The longer you are away from the game, the more likely a majority of your precious resources are stolen. Your rank on the leaderboard could be lowered. Your Clan becomes upset that you haven’t donated enough troops. These mechanics are all strong at driving reasons to come back, but also creates reasons for players to quit.

Idle games don’t suffer from this problem. Each time the player returns to the game, they are left with a massive stockpile of cash. It always feels like a bonus that they left the game. If a player leaves for a day, a week, or a month it only increases the amount of currency in their stockpile. In most economies this would be troublesome. Not in Idle games. Because the growth curves are exponential, leaving a game to infinitely generate a low income rate is absolutely fine.

For example, lets take 2 players. Player A comes back every day. Player B skips a week of play. Both players are generating 1 million cookies per day at this point in time. Player A, the active player, returns day 2 and receives 1 million cookies. Player B, who skipped the week, returns to have 7 million cookies. Player B can clearly purchase far more upgrades than Player A. Player B actually feels very rewarded for leaving for so long — they are rewarded with a very long session which they can purchase many things. However, comparing the growth curves Player A purchased many upgrades on that second day. So Player A by day 2 is already at a new growth rate of 10 million cookies a day. Player A is clearly growing far faster than Player B, but both players (because its a single player game) feel they made a smart choice. Player A is rewarded with faster progression. Player B is rewarded for waiting so long. It always feels good to return, but returning more often gives you faster progression.

Mobile games should strive to create this feeling. It should never feel like a punishment to come back to the game.

Players should be reminded that coming back often is a benefit, but coming back at all is always a bonus.

For this reason most farming games have shifted away from FarmVille’s model. Instead of withered crops, there’s low storage limits. In Clash of Clans, they incorporate shields and enforce looting limits to make sure players dont feel that not coming back feel too badly.

#2: Sessions ease the player away

Coming from my previous post on Flexible Sessions, the perfect mobile session finds a way to naturally push players out of the game. This is necessary for pacing and long term retention. Strong mobile games give strong reasons to come back (see above!) and strong reasons to leave the game. Idle games have mastered this natural prod of players out of the game.

As Idle games push players to invest in automatic revenue generators (ex. Grandmas in Cookie Clicker) over manual revenue generators (manually tapping on the cookie), players inevitably will reach a point in the game when they just have to wait. The player can purchase small upgrades fairly rapidly, but they know to make the next big leap of progression its smarter to purchase the more expensive upgrades. So, they leave the game feeling smart about their decision.

This is the exact point which the player, themselves, have opted-in to leaving the game. Naturally, the game has prodded the player to leave. Mobile games must strive for this. Create a situation which the player feels smart about leaving your game. Idle games have even managed to do this without timers, without social appointments or any other tacked on system as discussed in Player Commitments.

Create a situation which the player feels smart about leaving your game.

#3: It eases the player from core to meta gameplay

The first experience of a new player is very simple. In Clicker Heroes: A player just madly taps an enemy monster. In Make it rain: A player flicks heaps of money into the air. The first experience is addictive and immediately fun. Its obvious how to get better – tap or swipe faster. Players quickly master this mechanic and it feels natural. However, this mechanic’s interest quickly burns out. After the first few sessions, players are quickly tired of having to manually collect.

This is when the game offers a bait and switch. You came for the simplicty of tapping, but what you’ve been given is a game that is all about managing resources and upgrades. Players shift from tapping to managing which upgrade to purchase next. This clever switch means players that would have been burnt out from the simple mechanic are now thinking about long term decisions in the game. Which upgrade is the best value? How do I optimize my growth?

Mobile games must master this bait and switch. Players expecting to come into any mobile game will expect some core gameplay that mimics what they’ve played in the past. Playing bejeweled for Candy Crush, playing command and conquer for Clash of Clans, or platforming for King of Thieves. However, as a free-to-play designer your job isn’t to just hook these players with fun intial mechanics. You need to find ways to retain these players for years. The best way to do this is to switch the player from focusing on second-to-second core gameplay (tapping cookies) into longer term decisions (optimizing progression). Idle games clearly show a blueprint of how to accomplish this, regardless of the core gameplay.

Looking to the Future

Idle games are big and going to get bigger.

Anthony Pecorella gave an excellent talk at GDC 2015 on Idle Games summarized here. Clearly with the success of AdVenture Capitalist, Tap Titans and Make it Rain, more developers are taking notice.

The genre is ripe for innovation. Recently CivCrafter came out. A take on the idle genre with multiple resources and battles. Tap Titans has shown that the genre can apply to the auto-rpg genre. I believe that the progression systems in these games can really be applied to any genre. Replacing the core game play with a puzzle mechanic, an RPG battle mechanic, a Simulation theme, Arcade gameplay are all possible angles.

The key is to design the bait and switch: give the players the game play that is addictive and fun in the beginning, but eventually nudge them into purchasing the automatic resource generators. Players can then make the choice between grinding the core gameplay, or leaving and gaining the benefit just by waiting.

Get ready: the future will be all about games you don’t play.