In the past, our attack against the humans failed, but this time, we won't fail. You must fight off humanity's defense lines, but beware; they have built a special energy field that will try to make you dizzy! Everything will be much harder than a common arcade shooter game...

P or space bar - pause game
M and N - Mute music and Sfx
Arrow keys - Move
S - Shot
D - Drop bomb

There are extra instructions in-game.