There is only one way in

Save the damsel, but is she in distress?

Max out any skill of a Legacy Mode, OWC, or Online Gyms boxer

Knockdown Mason Brooks in under 3 minutes in Champion Mode

Defeat Ricardo Alvarez in Champion Mode

Defeat the prison gang member in Champion Mode

Make a 100 m (109 yd) jump (any game mode)

Drive at 400 km/h (249 mph) for 5 sec. (any game mode)

Drive around and hit 100 AI controlled cars and destructible objects

Obtain The C4 license

Defeat 70 enemies with the M4

Defeat three enemies with one explosion

Find 20 treasures