Ah, 3D asteroids. Ultimately, while it's a captivating idea, I don't think it really worked out too well. The main things that stood out to me as not a lot of fun was, asteroids were really far away, I couldn't tell how far away the asteroids were in order to know how much to lead them, and because I had to go into turret mode, it was super easy to lose track of 1-2 asteroids and then lose almost instantly. That element reminded me of an earlier game you worked on, UFO Cattle Battle - in your game here, you do have the red laser traces, which were an improvement.
All that said, it looks pretty cool, the ship effect, the planet and environment look pretty well put together, it was actually really enjoyable to just fly around, and I was looking forward to what the game might play like.
But, in the end, it feels kinda unaccessable and unfun? I think to start with you'd really have to find a way to make actually shooting the asteroids feel more enjoyable - explosion effects, maybe a scanner that let's you know where to aim to lead them correctly, or, maybe ditch the manual firing and have the ship auto fire cool homing missiles that would be neat to watch. If a solution was found there, perhaps next the gameplay could be made faster, doing 60 seconds to defeat a wave, rather than a wave every 60 seconds. Maybe with the mother ship jumping back to warp and hitting another asteroid field as the next level?
It seems like ultimately this game idea has some really tough to tackle gameplay issues, and I think you had a good stab at putting something together, and there's definitely some meat on this idea. It was really interesting to see it in the flesh as is, and have a play. I thought you put together some nice technology for the game, too, and I really do think it could go places, given enough time to figure out the issues that were brought to the forefront.