This was a pretty enjoyable game overall but I think that making the player aim with the mouse and pressing the buttons with the mouse is a bit wanky. You maybe could of made it so that 1 = shooting and 2 = moving sideways. I also think that shooting should of been on the left mouse button as that would made it a bit easier to shoot. This might be a nit pick but whenever I move the plain background makes it kind of hard to know where I'm going.
Other than that it's a good game and also pretty fun!