No. As long as the gun is, you need about three times the space-to-character ratio. Not to mention that you need extra space outside of the area the character is able to move, so the player can aim down, for example, even while the character is in the lower left corner. Which currently cannot be done with any precision.
The threshold of interactivity is also irritatingly small; the tiny "screen" size promotes the tactic of firing well ahead of what you can see to fish for enemies, but hidden from the player is the fact that an enemy can be placed maybe a half screen-length outside of view and be completely ignored by the gun-vomit.
You've also undermined your goal of having a "fast-paced action platformer" by everything being one-touch kills. When the consequences of flailing are dire, action stops resembling hectic throwdowns and more closely resembles sniper positioning. Every action must be carefully considered, and nothing can be left to chance--the result being your game is much more deliberate than you seem to think.
Also, the hat is part of your hitbox? Counterintuitive, and feels like being cheated when you get hit there.
All in all, this has the makings of a good game, but there is much to be learned about design before it gets there.