Here is the full list of all 20 South Park: Tenorman's Revenge achievements worth 200 gamerscore.
Complete the first level
Defeat the first boss
Defeat 100 Ginger Minions
Join a co-op game and successfully complete a level.
Barge through 10 walls with Cartman
Let's throw the ball around with Stan!
Infiltrate 10 Ginger Robot defenses with Kyle
Perform 20 high jumps with Kenny
Host a level in Multiplayer (online or local)
Collect all Time Cores in any level
Collect all the megamen in the game.
Use all weapons in the game once
Use all four superhero powers
Glass half empty
Earn a Gold Medal on all levels with any character
Find all secret areas in the game
Complete the game without dying once
Scott Tenorman REALLY must die!
Complete every level in any mode with each of the 4 characters
Complete the game in MP mode (online or local)