Hey mate.
As the game is rather simple, there isn't a lot of feedback that can be given, but the jump feels rather floaty. Usually, in games, the "falling part" of the jump is shorter than the "Jumping part". Maybe consider watching this video by GMTK.
Also, maybe consider juicing up the game with some particles when killing enemies and walking.
There wasn't a lot to do, so maybe adding more enemies / more to do would have been cool.
