Spectrum

This is a short game that you can probably finish in about 15-20 min if you see what's going on.

I compare it to sudoku because it has the same property that if you think about what moves you make A) it's fun, B) you arrive at a solution much sooner. but you can also win the game without thinking at all by trying different combinations. If you were an unthinking computer you might try an exhaustive backtracking algorithm which always finds the solution but isn't much fun.

Being a human, and understanding emotions and the connections between them and the elements in the game, you can make more logical choices.

I personally feel the game has a subtle pro-Christian message, though being an atheist myself that neither increased or decreased my opinion of the game, but in the end (Spoiler - click to show)it's all about forgiveness. This, whether Christian or not, is a good moral to any story.