Controls

• Click a cell: Select cell
• Arrow Keys: Move selected cell
• A, B, C, D: Change selected cell to a new value
• Z: Undo moves
  
• P: Show replay of your moves
  
• R: Reset the game. Modified cells keep their new values.

This implementation does not enforce all of the game's movement rules. Detailed rules can be found here: https://adventofcode.com/2021/day/23