Before you start the game you can get a few extra lives by completing the practice driving mode. You will start of with 1 more extra life for every time you complete the driving practice mode. You can also get extra bullets by finishing the shooting practice mode before starting the game.

Earn 100 Extra Bullets in Regular Mode Defeat Shooting in Practice Mode
Earn a Raw Meat Bonus in Regular Defeat Street Fighting in Practice Mode
Free life in Regular Mode Defeat Driving in Practice Mode