The aim of the game is to protect your secret documents from the aliens that recently found your base. This game combines elemental towers with a modern concept.
You will use turrets to take down the alien ships. Turrets use the power generator, and it's your job (also) to keep the power going. When the power gets low, tap left and right keys alternatively. If the aliens manage to steal 7 documents (lives) then you lose the game. Try to defend the last stretch with powerful turrets. If you hold M and click a turret, the turret menu comes up. From the menu you can either ugrade a turret, sell a turret or just check how a turret is doing.
The point of the game is to click on turrets from the shop and place them on the playing field. Then you will need to defend against the alien attackers while keeping your power up. Remember there is a second menu page and to upgrade it's m + click.