That's a really great arcade experience. The sound and graphical effects enhance it a lot, but the gameplay stands pretty well on its own. The burst powerup was very satisfying, but it could have used a wider variety of powerups and weapons I think.
I might have liked independent movement and aiming controls - I tried the desktop version with an XBox 360 controller to see if that was how it was implemented, but it did not work at all. The desktop (MacOS) version also ran really poorly for me - not sure what that is about as the web version was just fine.
Overall a very juicy and fun game