I'll give you a fair review based on the fact that this is admittedly unfinished. Player vs Bot is okay, though I have to see the rest of the game before I comment.
You've done a solid job with the graphics and sound, and the 3D objects are animated very well. The ship designs are cool (particularly the green ship), and battlefield background looks great with that
mist of color. I also thought the floating spaceman was amusing. The skulls look bad-ass.
I can dig the music you used for Deathmatches; it adds levity to the game. But in any other mode -- if you do single-players missions, practice, or story mode-- I would go back to something a little spacier.
I like the different types of upgrades. Instead of just the typical missiles, flamethrowers, and lasers, adding in the asteroid and black hole upgrades makes things interesting.
I enjoyed the scene on the main menu. It makes a little more sense after reading about it in your response below, but the images are pretty creepy, with the "night riders," the flashing lights, and the cars going by. The way they crash and suddenly ascend into the space for battle actually has some story possibilities.
Some issues:
I found the game screen so large that it was unplayable if it wasn't on full-screen mode.
I find the ship hard to control, especially no breaks. I understand reverse-propulsion stops you, but it was a struggle. I rarely had time to change direction and focus my aim on a skull-upgrade, for example, before the AI had suddenly turned around and collected it. I've gotten so few skulls that most of my kills have been with just the photon gun or collisions.
Once the players starts a death match, there's no way to quit back to the menu. Unless I missed something, I had to wait until someone achieved 15 kills or reload the page. I didn't see a pause button either.
I had Ship 1, the red and blue one, stop responding in two separate games. The arrows and the space bar just suddenly stopped working and the ship drifted aimlessly. I though an enemy with a black hole upgrade was causing it, but that doesn't seem to be the case, as Player 3 was moving around fine, and the problem continued after the black hole disappeared.
Periodically, ships run out of ammo, but there's no indicator as to when this will happen or how to solve the problem. Since there's no way to replenish ammo without picking up a skull, the original photon cannon should be unlimited. With the computer stealing all the skulls, the only other way I could see to solve the problem was to waste a life. And if the upgrades are finite, we should see a meter or a counter showing us how many blasts are left.
The AI is a little cheezy. It steals all the skulls even when it has a better weapon, and the way they turn on you at the beginning of the battle is frustrating.
I think I can see an weapon overheat bar under the character hit points. Is that what it is?
Do the black hole do any damage or just throw ships around the screen?
Keep working on it. You're off to an awesome start. I really hope to see the training levels go up soon, because that would be a big help. It was the first place I tried to go. And lastly, ARE you working on a story/mission mode, or is this just meant to be a PvP game?