Courtesy of  Lennart Steinke

How to Play - Aim with the mouse. Click to fire a laser beam.
As soon as you get close to the center or right border, the tank will move in this direction. You can also move the tank using the Cursor center / Right keys.
The laser needs energy to operate. This energy is always regenrating at a slow rate.

Display - Weapon energy is displayed in the upper center part of the console.
Your score is displayed below the Weapons energy.
The Radar in the center is showing all enemy ships. Ships draining energy are red.
The remaining energy of the base is in the upper right part of the console. As soon as this energy reaches zero, the game is over.

Power - Ups - If you destroy the alien attack sphere (this sphere needs several hits to be destroyed) you will get one of three powerups:
W - Weapon Energy: Your laser will refill much faster
S - Speed: Your tank will much faster with this extra
E - Eneregy: This will refill the base's energy