Just so you know: there's currently a bug in this game where your HP and score aren't reset after you die. You start out subsequent playthroughs with 0 HP (dying after 1 hit), but keep your score. You may wish to fix this, as it makes it very easy to get a high score. Also, your score doesn't update until you get hit.
Anyway, this game has an interesting mechanic with its randomly-generated levels, and certainly lives up to its arcade inspiration with its brutal difficulty. I found the controls a bit awkward to handle, since your character's jump feels floaty, but this isn't too much of an issue. My main complaint is that the random generator often places enemies in positions where they're difficult or impossible to hit without getting shot yourself.