The graphics and music were nice. There were also lots of nice touches with things like the camera movement. However, there are quite a few things that could be improved: the key bindings aren't great, there are no checkpoints, the melee weapon is useless, enemies take too many shots to kill and enemies also attack you when they're offscreen.
So let's talk about why I'm not a fan of the key bindings:
- Move with A and D; that's fine. Perhaps add left and right arrow as well, but maybe that works already (didn't check).
- Jump with Space, but dash up with W + shift; should be jump with Space or W and dash up with either one as well.
- Melee with LMB and shoot with LMB + RMB. Why not shoot with RMB or equip weapon with 1 and 2 (use weapon with LMB)? Perhaps you can just remove melee and have shoot with LMB.