It's a competent top-down shooter with a cool premise. I had a lot of fun!
I'm conflicted on the supercharge. In the early game, I never stopped using it. None of the enemies were quick enough to outwit me using the small screen space, and one-hit kills and quickly moving to the enemies to harvest XP made it much more useful.
However, once my uncharged shots starting doing one-hit kills and more enemies started appearing on the map, being able to cover the whole map became more important, so I stopped using it at all. It wasn't even worth it to run away from fast enemies, since shooting them is easier.
It's the kind of feature that's balanced only if enemy and upgrades are balanced within a narrow margin of error. It's a good idea done a bit haphazardly.
Also, while the sounds were not deafeningly loud, my ears (and my loudness recorder) could tell that they were peaking near –0 Db, and it sounds quite bad. (Those red blocks are where the sound is peaking).
Otherwise, great work!