After a few months of work I'm releasing the Indev version of Game Blocks. Game Blocks is a Game Construction Set similar to Super Mario Maker and Adventure Construction Set. This is still in-development (hence "Indev") and experimental, but there's enough there that you get the idea.
Instructions and download link are on the main itch.io page:
(Hopefully I didn't mess up the HMTL...) EDIT: Okay, that's better.