Here is the full list of all 20 South Park: Tenorman's Revenge achievements worth 200 gamerscore.
Collected all megamen in the game
All secrets are revealed
Completed the game with all characters
Completed the game without dying
Completed the game in MP mode (online or local)
Gold Medal champion
Joined and successfully completed a level in co-op mode
Hosted a level in Multiplayer (online or local)
Collected all Time Cores in a level
Defeated Robo-Scott Tenorman 2.0!
Super Power Sampler
Activated 5 switches with Stan's football throw
Glass half full
Barged through 10 walls
Used all weapons in the game once
Defeated Robot Tenorman 1.0!
Defeated 100 Ginger Minions
Infiltrated 10 Ginger Robot defenses
Performed 20 high jumps with Kenny.
Completed the first level