I passed the timer, but there was no fanfare!
It's a good game loop, but a little variety would go a long way. The winning strategy - of circling around the middle - can get stale over time. I enjoyed managing shooting and not dying - since holding down the button reduces your health and makes you shoot faster, wheras not shooting resulted in recovery. One or two more enemy types introduced about 30/60 seconds in would be very nice. I liked how your hitbox got bigger during the dark periods if you shoot, it makes for an interesting risk/reward balance.
Good work!