Things I liked:
-It's overall fun to play.
-The metroid artstyle, and art in general, is great
-The variety of music fits really nice with the art and environment
-The metroidvania genre is well applied (reminds me a lot of super metroid)
-It's really polished to be a Jam game
-The bosses are simple, but managed to surprise me
Things I didn't like:
-Some areas are overcrowded with enemies wich makes it annoying instead of difficult
-Once you die you lose a lot of progress, (not sure if it was intended or the savestates weren't working)
-You said there was a more stable downloadable version, but nothing happens when I try to download it