The cool-color parallax background and kickass superhero music. I'd love to see a story mode from this game. Played it a lot one night and got all the upgrades, even though the final Gun Speed upgrade is bugged and can't be purchased. My high score is 8000$ in one night.
I read another comment saying that the laser is weak. That's funny, because the way I see it, the gun is weak. Even when the laser hadn't been upgraded yet, I found myself constantly using the laser but rarely switching over to the gun. It is good that there is no clear victor as to which of these is the better weapon, but I think that going forward, you should give the player some incentive to use BOTH weapons, even if they prefer one over the other. Perhaps one new enemy has a reflective surface that makes it resistant to the laser, while another new enemy has armored plating which makes it resistant to the gun?