I built automatic replay and hot code reloading on top of the Phaser game engine, using my compo game Jumpcoins for testing. It captures game state & inputs, loops, and loads code changes right into the running game without starting over. These, especially combined, make an EXTREMELY satisfying dev experience!!

I couldn't upload the demo gif to the LD site since it's a minute long, but you can check it out here.

I really wish I had this setup in time for this past LD! What does your development feedback cycle look like?