Overall, UFC Undisputed 2010 on the PSP is a fun and engaging game that's worth playing, especially for fans of the UFC. While it's not without its flaws, the game's career mode and solid gameplay make it a worthwhile experience.
A major criticism is the rapid stat decay. If you don't constantly spar or train, your fighter's attributes drop, which some players find tedious.
Get your core stats (Power, Speed, Cardio) to a "milestone" (levels 30, 50, 70). Once you hit a milestone, your stats cannot drop below that number.
Make sure your PSP is running the standard UMD or a clean ISO. These codes work on all firmware versions.
Hold L + R and press Up, Down, Up, Down, Left, Right, Left, Right . Result: Adds 50 bonus attribute points to your CAF pool. You can distribute these freely before starting a new career. This gives you a massive head start against the AI.