Several small issues make this game a "could be"
Well it has some BIG problems with collision detection. Not because it collides when the ship doesn't, but in the way you made it, the ship somehow is either too big or an exploding animation can still hit you even thou the mine is already destroyed.
The other problem I find is that even thou the game is supposedly focused on multitasking, any one could easily get a second person in the keyboard to control the other ship while both of you mash the space bar.
Still, a creative experience. 7/10.