Great game. Could easily see a sequel (or at the very least a level-pack), possibly with different resources and/or organizing upgrades in a tech tree. Lots of potential to do more with this concept, but still fun in its own right.
Score in team mode should be based on win / loss of your team, not based on whether or not you get (individual) kills (or, if so, only secondarily). The current scoring really ruins any teamwork in team games.
Would really love to see team win incorporated into scoring, somewhat. That is: if your team wins, you should get some partial credit, even if you didn't land the killing shot on any enemies.
The fighters really need to be stronger. As it is, you are quite literally better off not having them at all. The amount that they add, in terms of distraction and (piddly) added firepower, is more than offset by the added difficulty of shooting down dodging enemy ships.
In short, if you sell the fighter bay, you can very easily pick off all incoming enemy fighters, and you're better off.
Great game! The biggest thing needed is the ability to toggle the cannon on and off (or, really, just leave it on all the time). My finger is aching from holding down the mouse button so long.