A hidden gem. The world is interesting to explore and feels like one big maze. The boss fights are fun.
Some complaints.
1. Dying sucks. Bad. You lose all your primary and secondary weapon powers and you have to grind all that back before you retry the boss. I just ended up never using the secondary weapon because releveling it for the 239084230948290th time sucked.
2. I saw no reason I should have stopped firing. It sucked having to hold down the shoot button for the entire playthrough.

This game has a cool artstyle and cool boss designs but feels otherwise flat-out unfinished. You swim around a single map shooting very unthreatening enemies with a really underwhelming gun and there's basically no other flair or meat to it. This evoked no emotion from me and simply gave me something for my hands to do that reminded me of shooters that are actually good. Had I payed more than 2 bucks for this I probably would've removed another star.