Vicious creatures now occupy 8 vital space stations in their effort to conquer our peaceful solar system. It is up to you to destroy these locations and their evil inhabitants in order to save the human race. There are 16 different aliens and to eliminate them all you'll need an Energy Sword. But that's not all. Those creatures will use up your oxygen supply and sap your strength. Destroy them and win back energy pods and oxygen bottles. Find sonic keys to open sonic doors; gain access to the station's re-entry code and then battle your way to the self-destruct mechanism. Once you have inserted the code get to the teleport chamber fast or you will be destroyed along with the space station!