Nice offering, I can see this being really fun with some more polish! It's a shame you didn't manage to adapt the game idea to the theme, but the gameplay loop has legs.
One thing that struck me is that the shooting doesn't seem to change direction on the y axis, so I couldn't shoot uphill which was strange to get used to. Your arena is also very busy, with tons of shapes around. This is cool, but does make it quite difficult to navigate. It does show off what your 3D character controller can do though!