Playing On Harden
When your playing on harden you will find out that you will die easier because 4-6 shots will kill you. The key to staying alive is first beat the game on normal or easy because if you have not found out the enemies will come out and stay in one spot or just move from side to side. If you already know were your enemies will come that will make surviving a whole lot easier. Also try to sit back take cover don't try not to take on more than 3 or 4 people by your self let your partner's get in front of you and use them as shields and since they cannot die you can also let them kill ever one (note: this will take along time but if your not that good at least wait a while before running out to fight). Also, don't try to stab every body that's close to you because they can easily kill you with one hit as will with on hit or they might shot you to death before you get to close.
Walk On H20 Glitch
For this to work you need to have already beaten the game, once you have, go to quickplay & select american and scroll left 2 times and then press a on oil rig confrontation and then the screen will go black and then will light back up and you will hear a guy say "Reports from AWAX" and keeps talking don't press start wait till the screen goes to the captin talking to you when he is done talking go up the stairs and you will see at the side of the 2nd stair there is an edge go on to it and then look up walk back down the stairs looking up and whail looking up walk off the dock and you may be walking on water. If it doesn't work the first time you have to do it again from step 1.