A few thoughts, after a first go on the beta:

I generally like 'Thrust-style' controls, but I'm not finding the current controls to be precise enough for aiming - A very quick tap on the rotation keys results in about 10-15 degrees of rotation - which is a lot when aiming at a small target. (Maybe support for analog controllers would help here - and in the future, different weapons would certainly help - spread shots and homing missiles etc)

It seemed like there was a bit of input lag, too - I'm not sure if that's related to the networking implentation, or just local (client or GPU driver settings)

I felt that reverse thrust should be allowed, rather than just braking (although with a much lower top speed?). Braking alone doesn't seem that useful, as there's a fair bit of drag, so you slow down quickly when you stop thrusting

I'd also suggest having the camera zoomed out a bit further (even if it makes the player ship tiny) so you can see more of the action, and so it doesn't scroll so fast. (Maybe the player ship shouldn't be completely locked to the centre of the screen, either?)

Also, it needs to be much clearer what is a 'scenery object' (background asteroids) - so they don't get confused with 'gameplay asteroids'!