From the Publisher's Website:
Aliens: Game Over is a role-playing game set in the far future of exploration, where United Systems Military Marines venture forth to meet extremely hostile alien life forms... and kill them.
The future of Aliens: Game Over is bleak: megacorporations and mercenary companies run rampant. And yet there is an old world nobility about the Marines Corps, who still uphold the virtues of honor and loyalty. Perhaps most importantly, the Marine Corps has balls of titanium and is fearless in the face of any foe, human or otherwise.
Aliens: Game Over is a massive supplement for D20 Modern that contains 2 new races, 14 new occupations (including 8 corporations and 5 marine divisions), six new feats, new psionic powers, more equipment than you can shake an Armat M41A 10mm pulse-action air-cooled automatic assault rifle at (including the dreaded ATAX and HARDCore power armors), 14 new advanced classes, dozens of new worlds to explore, a mission generation system, and 28 new monsters. Did we mention lots of rules about Aliens?