Instructions
Start the game on any mode. Begin moving around using the direction pad and look for weapons to collect. You need more than one weapon in order to switch between weapons.
Press and hold down the left thumb-wheel to pick up a new weapon off of the ground. You hold up to four weapons in your inventory, but must trade a weapon you have for a new one if your inventory is full.
Press the red "B" button on your controller to see you inventory on the bottom of the screen. Press left or right on your directional pad to select the weapon of your choice.
Hold down the "B" to select the weapon that you want to use. Hold down the "B" button again to select another weapon in your inventory.
Tap the red "B" button quickly to bring up a secondary weapon, such as a grenade launcher or pistol. Press the "White" button to target an enemy and then press the "A" button at any time to reload your weapon.