To unlock bonus characters, earn a Gold medal in the "Arena Del Toro" and "Getting Tanked!" levels. Also, earn a Silver medal in the "Ay Mama!", "Carne Cesar", "Rooftop Ferno", "Abandon Ship!", "Nice Wheels", "Supervilla!", "The Hacienda", "The Jungle", and "Ultimate Underworld!" levels.
To activate Cheat Mode, enter "ERNESTO" as a profile name. You will receive invincibility. Additionally, while playing any mission in Single Player mode, press Select to complete the mission with a "Gold" rank. Pressing Select in a Challenge match will allow you to pass one part of that match. On certain levels and challenges after obtaining a "Bronze" or higher, "Silver" or higher, or "Gold" rank, you will unlock more playable characters and maps in Multiplayer mode. Continue to do this to unlock everything.