Really nice game.
The pixel art is pretty good and follows the colour limitation well, animations are reasonable though they could probably be a little better.
The spikes are a bit tricky to see.
I like the ambient music although it seems to cut out before looping and is a bit quiet. The game definitely needs some sound effects though as they seem to be missing.
The rune puzzles obscure the lower part of the UI when playing the game windowed which made me think the game was bugged until I played it in fullscreen.
It's hard to see how the mechanics tie into the jam theme outside of the use of the colour limit.
I enjoyed MushRunes and think with more work, content and polish this could become a good metroidvania.