I had the same problem. About 3 days ago, I was in Rundown, and the other team were unbelievably good(Score around 4000 to them to around 300 to us!) and when I looked at kill-cams, I seen why. Their screens had red squares around where our players were. Also, they could jump high enough to jump over buildings, and amazingly fast. I quit out of that game, and joined a different one. Later on the same thing happened, except that I spawned into the game late, on the cheating team. I couldnt even control the player he was going so fast. I almost immediately got booted off the team. It happed a third time, with me on the normal (losing!) teamwhen the whole thing glitched and we were all sliding down the side of a mountain, but still able to shoot each other. Then everything froze, and my challenges, guns, emblems, and tags were all completed, and I was level 70 again!
I didnt really know what to make of it, so I asked my friends that play mw2 a lot to see if it had happened to them, or at least if they had heard of it. Not one of them had. I figured it was a screw-up on the on-line systems for that day. I wanted to reach level 70 and unlock everything myself, so I prestiged and started again.
I was playing today (I had leveled back upto lvl 26 or 27) when a similar thing happened in Scrapyard. There was a noise, and I couldnt move. People were shooting me, but I wasnt dying. Then the writing came up telling me that I had completed all challenges again! The game got cancelled almost immediatly, with an error message saying that the game was cancelled due to security issues with the host.
I had my NAT Type set to open. Thats the only thing I can think of that might have caused this. My friends are all moderate. Does anyone know if this maybe the cause of the trouble? I want to revert to my initial score ( I was around lvl 54) and finish levelling up myself. The whole point of levelling up is the sense of achievment in the game, but this glitch ruins that completely
<message edited by Johnos on Thursday, January 13, 2011 7:19 PM>