Unlock Theatre Mode
Complete story mode once to unlock theatre mode.
100% success rate. 

Unlock Devil Jin
Either complete the "Devil Within" side game or play about 200 games in arcade mode to unlock Devil Jin.
50% success rate. 

Unlocking Characters
Keep completing story mode with different characters until everybody except Devil Jin is unlocked.

Unlock Eddy Gordo
Eddy Gordo is an extra outfit you buy for Christie for 500,000G.

Go to: Tekken 5 Info Page | nGaming Home Page.