Jetsam, our upcoming iOS puzzle game, originally had a bit of a problem.

It was too hard.

The game, which revolves around the titular robot collecting pieces of space junk in a zero-g environment, could ruin the player’s experience in a number of ways.

Destructible environments meant that players could trap themselves in situations they couldn’t escape from.

A malicious sequence of wormholes could get players caught in an infinite loop.

Given that we wanted the game to have a full-fledged level editor, this caused problems. We couldn’t just hand-wave away these scenarios and exclusively design levels where these situations weren’t possible – the community was eventually going to get ahold of the level editor, and they surely wouldn’t be so merciful with it.

So we came up with a game mechanic that solved all of these issues: fuel.

How does fuel work? Well, it’s pretty simple really. Every move costs the player one fuel point. Run out of fuel and you explode. Explode, and the level restarts.

Fuel is what we call a “Hidden Rail” mechanic. Even though it appears benign, its intent is to prevent the player from getting too frustrated with him or herself. Believe it or not, this happens a lot – especially in puzzle games. Our game is pretty openly inspired by the Pokémon Ice Cave puzzles of yore – so posts like this one on Reddit really resonated with us and underscored the need to keep players from getting frustrated with Jetsam.

Running out of fuel lets us loudly tell the player “TRY AGAIN,” which prevents them from reaching a moment of frustration on their own after many failed attempts at a situation that might actually be impossible. We don’t want to waste our players’ limited time by letting them struggle indefinitely against impossible odds. Fuel also constrains the total number of moves players can make on a given level, in effect making levels slightly easier and giving us another difficulty lever to play with. The same level can be radically more or less difficult if we tweak the starting amount of fuel.

Hidden Rails (like Jetsam’s fuel mechanic) can help you as the game’s designer shepherd your player into enjoying your game in the way you intended. By identifying undesirable behavior patterns, you can use the invisible hand of design to break players of those behaviors – whether it’s through the sweet embrace of explody death as in Jetsam, or otherwise.

Constraints, counterintuitively, can often bring more creativity to bear. Adding fuel in as a Hidden Rail actually gave us more ideas, which led to further developments in the game, including collectible fuel packs, fuel maximization challenges, and a whole host of other things beyond the scope of this dev blog post.

We can’t wait to tell you about those soon!

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