-You give an awful lot of stuff for just this first room, and the only thing that could really make much difference is the Arms Barrier (e.g. if you add in some damage later on which would break Lv3 if you don't have it). Some extra ammo/the Turbocharge might be useful if it were optional just before the planned Omega fight. Also, you could probably drop that initial ammo count as low as 20.
-The only area so far that really requires careful maneuvering with the Machine Gun is the spike section just after getting it, and it's awfully short. It could easily be extended over to the right wall. Or, you could add in some more Crows (turn on the invincibility flag so they don't go haywire) and base the area around weaving through them. Make the player really work for that reward!
-The block mazes are a bit slow and dull at the moment. For the second one at least, you could try putting in some enemies, along with some clear tiles to show the player where they are so they can gauge how to deal with them. Would also give that healing room a reason to exist.
Don't let all that discourage you, the map design is sound and I didn't see any scripting errors in it
Just remember that you should focus on the Machine Gun, as it's up to you to showcase its potential.
