How about you change the controls to WASD AND the arrow keys? A = Left D= right S= Shockwave (now that just makes sense) W = Melee. And then, Left to aim left; Right to aim right; Up to move right; down to move Left. Me being a gamer; I'm used to using WASD and the Arrow keys whist playing a game; and I think the controls would be less awkward if you did.

I feel like you should add some sort of object that allows health restoration. It could be like; a purple ball; somewhere on the map that would spawn when a certain criteria is met; like; when you kill two foes; or when you reach a certain amount of health. Also; I feel like the circles are a bit overpowered in that they have a huge range. even after it's fired; it still travels for a bit before fading out (cool feature) but even while fading it still does damage to you. Therefore; I wonder what it would be like to have a slightly better range....

the transparency is what gets taken away from your health so It might damage you when it is very transparent, but it will only deal a small amount of damage.