Cheat: Movement
When choosing items to bring along for the hunt, after choosing a game type, go to “Hunt” and remove everything from your character. Then put everything back. The game doesn’t recognize the weight of everything that was replaced and your character will move as if he has an empty pack.
Unlock X-Ray Scope
Clear the game on any difaculty to unlock x-ray vision while using the scope.
Hint: Quick Crossbow Reloading
Here's a great technique for quickly reloading your crossbow. After each shot you take with it, put the bow away quickly, and then take it back out. The crossbow should be fully loaded once you take it out, even if it wasn't when you put it away. This gives you back the precious seconds you would have otherwise lost reloading your weapon.
