You deserve an extra point for the interpretation of "space"!
It's great that every enemy has it's completely own movement and attacks so you are scared at first and may fail at the first attempt to dodge, making the game more interesting. My favorite one is the laser-tie-fighter.
Graphics are simple but look polished, the animations are great too. Only thing I'm missing so far is a score or wave counter so I know when I hit my highscore :)