Retro Puzzle Maker
Retro puzzle maker is a toy I made back in December of 2018 – originally allowed you to create a short 8-level puzzle game for the NES, and download a rom of it.
Since then it has evolved into a full-fledge game creator, letting you use your own resources to create a game with 64 levels, with no code required. The game is open source, and tools are provided to hack on it, if you so desire.