Love me some space shooters. and this one had a fun twist. Anyway you wanted unfiltered criticism, so here it goes:
I get what you were going for with the slidiness in space, but you way over did it. It felt very awkward trying to control the ship, which made moving around unfun. Also I feel like you should have capped the max speed at a much lower speed, since going at light speed and accidentally running into an enemy was also not fun.
I think if you just tweaked all the movement values to make the ship controls feel responsive, smooth, and in general more predictable, the whole game experience would be way more enjoyable. If you really want to keep over the top sliding, at least triple the turn rate so you have some control of the ship with that.
Two things about your actual core game mechanic.
1. 30 seconds is an incredibly long time.
2. Enemies were chasing you even when they couldn't shoot.
If you shortened the role switch to 10, maybe even 5 seconds, the game would feel way more active and encaging. And I feel like making the enemies run away from you when they can't shoot would enhance the feeling of who is in control at what point, and make for a very fun pacman:ish back and forth.