This is my first PICO-8 game. I just posted it on itch.io yesterday for submission into the 20 Second Game Jam, so clearly you're not in for an hours-long game of chess with this one. The main game mode lasts 20 seconds of course, but the version I'm posting here includes a mode that isn't timed as well as a practice mode.
The idea for this game started with imagining a one-player type of chess that didn't rely on an AI-based opponent. You're presented with a 4x4 board with five pieces to capture. First you select a piece to start on, and you now have its moves available to capture with. As you capture pieces, you gain more moves. You lose by letting time run out or by landing in a spot where a piece can capture you. None of the pieces move unless it's to capture!
The knight is the only modern chess piece that made it into the game. The ferz, dabbaba, alfil and wazir pieces are from older versions of chess and often included in chess problems and variants. I made up the hound and boot pieces.
The web player version on itch.io ( https://robt-fm.itch.io/chemps ) takes you straight into the 20-second game. My devlog on itch.io, as well as the source here, has citations for code snippets and organizational principles that helped immensely along the way. I'll probably do another devlog at some point about why I picked the pieces I did and why an earlier version had pawns but I removed them (leading to the hound and boot).
Thanks for playing!