Description taken from PlayStation Portable version of this game

Aliens vs. Predator: Requiem is a third-person shooter featuring a lone Predator on a quest to hunt down acid-spitting and face-hugging Aliens lurking in Gunnison, Colorado. Based on the 2007 film from 20th Century Fox, Requiem has players engaging in fast-paced blasting and brutal close-quarters combat across levels with branching paths. Featured environments include forests, suburbs, warehouses, underground sewers, and more. The Predator can eliminate its prey by using a flying disc weapon, wrist blades, a hand cannon blaster, dual shoulder cannons, and laser trip mines.

A wrist-mounted computer allows the Predator access to thermal vision modes for tracking or cloaking technology to elude soldiers. As in the film and comic book series, the Predator is bound by honor, reflected in a point system that penalizes players for killing civilians. Points are used as currency to purchase equipment upgrades in between levels. In addition to hunting enemies, players must also find and destroy pieces of Alien technology. Solo Predators can participate in either the Story Mode or a timed Skirmish Mode. Ad-hoc wireless support is also included in a two-player contest to see who can kill the most Aliens. ~ Scott Alan Marriott, All Game Guide