Use the Triangle key to deliver the final blow to a boss.
Slow-motion and character select
Successfully complete the game on the easy difficulty setting to unlock the slow-mo and character select options.
Unlocking bonuses
Play the game well and get past certain levels to unlock bonuses such as "Slow Motion".
Killing enemies
Auto-face an opponent and jump in a forward motion or dive will help kill an enemy quickly. If you do not auto-face, you can just dive for cover or get away.
