This game is very polished, the mechanic is cool and everything works perfectly. I would not call it "pre-alpha" :)
It is not my genre (I never played another metriodvania - had to look it up on wikipedia) so it is hard for me to give you any advice. There are no obvious shortcomings ...
What I liked most where the boss fights - figuring out the mechanic and then applying the "win"-strategy was engaging.