I’ve got two games online that I haven’t listed here yet. Minewalker and Cube Roller they are both similar in general genre, which I’m kind of thinking of as an endless runner puzzle game. You have to keep progressing forward to keep from falling off the end.
Minewalker uses the minesweeper rules so you have to keep progressing through a minefield to stay alive. At one point the player was going to be a chess queen, in reference to the Red Queen that has to keep running to stay in the same place, but maybe that would have been mixing games too much. If I think of a good chess-based puzzle I might return to that.
Cube Roller was originally Dice Roller, but I switched it because not everyone is intimately familiar with the layout of dice and the numerical values didn’t really matter. With a little people cube, everyone will easily remember the hands are on opposite sides and the face is opposite the butt, etc. Whereas people might not all know that the opposite sides of a die always add up to 7.