For the first phase of the game: Its basically a shooting range minigame and thats fun. The spinning room makes me a little bit dizzy, but its not that terrible to be unplayable. It gets worse with faster mode (deciding demage the core more).
The boss fight is a classic bullet hell, which is also fun. Yet some juice could be added. Even small things like red flash and some sound effect when getting hit would do the game a big favor.
It is a pitty that the gamme can't be finished because of the bug with immmortal boss.
Good job releasing your game!