Safe Cracker is a game in which the user must crack a safe despite the distraction of an annoying fly.
I wanted to create a game in which victory was dependent on the user's ability to discern subtle audial cues over background noise.
The game consists of a lock to which the user does not know the combination. When the lock hits a correct number, a "ding" noise is played. If the user makes a mistake (such as continuing past the correct number, or changing direction prematurely), a "thunk" noise is played and the lock is reset.
The game would be too easy if the user could simply turn the volume way up. To prevent this, I added a background noise (a fly) which is played constantly.
The game is quite thoroughly impossible without sound. Even a brute force approach wouldn't work because there are no visual cues showing where the numbers begin and end, only a clicking sound that alerts you to their spacing. I am not aware of any other games where success depends on the user's audial acuity to this extent.
Once I added the background noise, I felt I had achieved my goal. It provides enough distraction that the player occasionally thinks they heard something when there was really nothing, and vice versa.
I underestimated how annoying the fly would be. I decided that in order to make the game seem satisfying, the player needed a way to kill it. Of course, this needed to be just as hard as cracking the safe with the fly present, since the game becomes quite easy with no fly. This adds another layer to the game: The user is constantly tempted to stop cracking the safe and attack the fly instead!