A fun little metroidviania. I found a couple issues:
When the game is fullscreened, the text gets gray anti-aliasing pixels. It looks perfectly non-AA at the size in the embed however, so I didn't remove points for that.
Trying to jump back up after falling from the double jump room can variously either black out the screen or let you walk outside the map. I thought it was intentional at first, since the text encourages you to try the double jump. (Unless there really is a secret there 👀)