Gas Tanks

Keep track of your partner's ammo: The amount of ammo for your partner's ammo is displayed twice: Once for the clip, displayed in green next to the weapon. The rest of your partner's ammo for their equipped weapon is listed next to the small bullet icon, either above or under their name. If your partner runs out of ammo and you have some that you can't use, it's better to let them have it.

Use healing items with your partner nearby: Whenever you use a Herb or First Aid Spray, make sure that your partner is standing right next to you. Healing sprays will always heal both partners when they are close together, and there are no penalties. There's only one reason to use a Herb when your partner is far away, and that is if you're in caution and an inevitable death will overcome you unless you quickly heal yourself.

Order your Inventory!: Your inventory consists of 9 slots. You have four "Quick Spots" in your inventory: slots 2, 4, 6, and 8. These items are automatically assigned to your D-pad. Pressing left on the D-pad equips the item in slot 4. A recommended setup is to have your two primary weapons assigned to two slots, a Herb/First Aid Spray in another slot, and the last slot with whatever you prefer. Grenades work well at the start of the game, and later you can swap a third weapon in it, such as the Magnum, Grenade Launcher, or Machine Gun (besides Handgun and Shotgun as primary weapons).