I like the neon palette. It's pretty unique, and gives the game a certain retro feel to me (not sure why). I like the overall concept of the game too. It's sort of a fresh take on a metroidvania.
I couldn't get the last piece of the door though :(
The 3rd piece was in the enemy that you collect by jumping on them and the 4th is in a section in the top-left, so you may have missed one of those (you didn't miss a lot though since the game's shorter than I wanted but wanted to be sure all the mechanics worked)
