The movement scheme threw me off, and the game description has a different "right move" key than in-game. It makes the game a bit harder but not more fun, I have to say.
It's a fairly standard set of mechanics, move, shoot, avoid damage, wome enemies track you and others are more like static obstacles. I'd call it a good start in the genre, but needs a lot of smoothing on the gameplay.
Also for the floor, any kind of border/texture on the tiles would have made it easier to tell where/how fast we are moving.