The floor cracks and turns to lava, burning any piece on it.
How to play
The floor is collapsing. After each of Black’s moves, a square cracks (orange outline), starting mostly from the edges. After Black’s next move, cracked squares turn to lava, and any piece standing there is destroyed, kings included. After move 15 two squares crack at a time. Nothing can enter or pass through lava. Check rules apply, and lava counts as an attacker: a king standing on a cracked square is in check, you may not leave your king attacked, and White may not end a move with the king on a cracked square. Checkmate wins; stalemate is a draw. No castling or en passant.
You play White against the bot. Tap a piece, then tap a highlighted square.