P1: Press arrows to move and space to use beam. P2: Press WASD to move and F to use beam. Alien guide: Green = 1 point. Blue = 2 points. Gold = 10 points. Diamond = 50 points. Purple = All red vanish. Red = -1 point. Orange = -1 life. Evil blue = Ghosts! White = Nothing. Black = Game over. Pink = 1 point and -1 point for other player. Pink aliens also take away a bit of the other players life, so if you get 25 of them, the other player loses 1 life. WARNING: Gold aliens sometimes make you suck things up without pressing space/F.
There are lots of other space speeders games, which you can find in my "intelligent life..." studio.