The species of aliens that compete against the Humans are the Gorlocks, Needleheads, and Brains. The games included Florgus Ball (Gorlocks vs. Humans), Mountain Menace (Needleheads vs. Humans), Greased Martain Toss (Needleheads vs. Brains), Can You Eat This (Humans vs. Needleheads), Obstacle Course Challenge (Humans vs. Brains), and Trivia Showdown (Humans vs. Gorlocks).