Just like sokoban, except instead of being played on a 2d grid, it is played on graph-like structures with strange topologies (e.g. loops, mobius strips).
Player must create as random a sequence as possible using the keyboard. Randomness is rewarded by pictures of random stuff.
Solving a maze is easy. Solve it with only audio output.
Audio differs in loudness at different pitches to tell you how close the wall is in front of you, to the left of you, and to the right of you. More generally, there is a continuous map A2P between angles (90 degrees left through 90 degrees right) and pitches (low pitch to high pitch), and another continuous map D2L between distances in meters and loudness in decibels. The fact that there is a wall at distance d from you on angle a is expressed by audio at pitch A2P(a) being at loudness D2L(d).
Player gets intuition by playing training level which plays audio while showing the maze. The video gradually fades out until only audio is left.
Adjust the sine wave coefficients to guide the bird through the pipes.
In the prisoner's dilemma, both players make their moves in secret, after which both moves are simultaneously revealed. One could apply the same principle to turn-based games like tic-tac-toe, checkers, or chess. In prisoner's tic-tac-toe, both players mark their move on their own secret board, then simultaneously reveal their moves. In the case of an invalid pair of moves, both players lose.