Hey, really like the style of your game, as others already said the visuals and sounds are nice - I think it just gets a little annoying when shooting all the time ^^
Is the spawnrate randomly set? Because sometimes it felt undoable in the first stage - especially with the pistol - and then in stage 4 I had the same spawnrate as in stage 2. I think having the difficulty lower at the start would help a little getting into it. Other then that very nice entry!