The Godfather

Full ammunition:
Pause game play, then press Y, Left, Y, Right, X, click Right Analog-stick.

Full health:
Pause game play, then press Left, X, Right, Y, Right, click Left Analog-stick.

All movies:
Pause game play, then press Y, X, Y, X2, click Left Analog-stick.
Tbone, Craig Kosikowski, and Max Aracil.

Unlimited ammunition and 1 million:
Reach the "Don Of New York City" rank at a 91.5 game completion.

Recommended weapons:
Do not waste money on safe houses. You can make it fine with just the ones you get in the story. Instead, save money for clothing and weapons. All the best weapons cost a lot but are well worth it. The Saturday Night Special is a better revolver and it will cost 75,000. The Assassin's Pistol is better gun and costs about 200,000. The Python a better magnum will cost 250,000. The Dillinger is a machine gun that costs 450,000. Finally, the Street Sweeper, which works like a shotgun, sells for 500,000 and will kill most people in one shot.