Just in time for the Game Jam I'm excited to announce the addition of Pyxel -- an 8bit retro gaming framework for Python. Pyxel has everything you need to build an 8bit game, from the image editor to a music editor (Repl.it doesn't support sound yet).
It's also easy-to-use and fun to play around with. The following is a speed-up play-through of one of their examples running on Repl.it. I used their editor to change the player's hair color.
Here is the repl: https://repl.it/@amasad/jumper
Start building your game by creating a new repl and selecting "Pyxel". Or click here.
Let me know if you have any feedback.