Hey, that is a pretty good start :)
I'm definitely not a professional (I only make games onto Scratch XD ), but here is the things that I discovered :
- Be careful with the hitbox, because if you are at the edge of a platforme (the first one near to the rocket), it give the impression the player is falling without moving at all. I asume it is because the hitbox of the player is a scare : try with a triangle looking down, it should solve the problem. Further more, you can climb a platform for about a second when your jumping, making it very easy (but that was maybe intentional XD ) + you won't fall until you unpress the right / left keys
- I don't know why but some times when you shoot, the fire goes above your head, not in front of you
- the number 8 of the gun never change
- the laser of the boss does not make any damage
- during the entire level you've got flying enemys above your head but they don't attack and they flew when you are trying to get close
Thats it :)
However it is a very good start, I wish you all the necessary to finish it properly and most of all, have fun making it :)