You probably noticed this already, but in case you haven't, you can cut certain animations of your items and weapons short while reaping their benefits on single-player.
This is especially helpful if you're being shot up by several enemies and need the auto-injector to stay alive. For the auto-injector, once the screen tilts and you hear the re-assuring hiss, you can switch to another item or weapon.
For weapons, once the magazine total reads its maximum, you can select another weapon or item and your gun will be ready to go when you next select it. You can even start a reloading animation just before climbing a ladder and reap the benefits of the reload.
The Power Tool is used to repair vehicles, but it can also be used to break down walls and kill enemies. It can even disassemble enemy tanks with the greatest of ease! Don’t overlook the offensive capabilities of the otherwise-innocuous Power Tool!
During the game, you’ll encounter plenty of houses that you can explore. Usually, your instincts will tell you to blow a hole in the house with a grenade. But you can save those precious grenades and use your knife to bust out the house’s door or windows. You can then jump on into the house and explore without having used any grenades!
To unlock the kits listed below (which unlock the corresponding weapon in parenthesis), insert the cheats listed at the in-game cheats menu.