2 things that I found, both sound related:
1. Some of the custom effects, namely the beams, have a pretty noticeable cutoff at the end. Rather than eventually becoming silent, the sound begins to damper, then just stops. Would this have to do with the tag, or was the sound file deprecated in some other way?
2. The low health beeping. While it's a good idea, it can get rather annoying if you can't find a health orb. A more subtle loop (like, well, the Metroid Prime health warning) would be better at indicating low health rather than BEEDEEBEEDEEBEEDEEBEEDEE.

Other than that, this is made of multiple kinds of awesome and win.