(adsbygoogle = window.adsbygoogle || []).push({}); 1.Requirements you and your friend need 2 controllers.
2.You make a party in zombies with both your controllers on, like if your playing split screen
3.you invite your friend to your party.
4.make sure when he joins he has his split screen connected as well
5.now your both in a party with your split screen so it should be 4
6.Start a online match and as soon as it said,s match begins in 2 or 1 you both back out your second controller and it should start with just you and your friend no split screen.
7.please hit the thank button for this little glitch or trick i haven't seen it posted.
8.If you need help and you have 2 controllers just add me on ps3 AMP3D_UP_AVIR3X

They do if you keep difficulty on original, otherwise I wouldn't have my rank.

Custom games count towards your rank the only thing that doesn't count is the highest round on the leaderboard. I got to level 37 and in that game i got skull knife but when i checked on the leaderboards for the highest round it didn't have my round 37 game I played.