Easy quick game
Use the following trick to get a combined clear time for the entire game of under five hours (to unlock unlimited RPG ammunition). A really easy way of doing this is to play under the Amateur difficulty setting and just run pass all enemies. Only kill story-driven enemies (ones that hold key cards or those that must be defeated to advance the game). Also, avoid any crates, barrels, or treasures. Attempting this with a friend instead of the CPU-controlled Sheva is recommended. Note: You do not need to purchase the infinite ammo in "Bonus Features" as you would do for normal guns.