...oh my god would you people please just ignore that Lorenso kid? That boy clearly has got... issues...
Really, just let him troll and ignore him.I'm having the same problem. It appears to occur when there's a lot of fog/dust/clouds on the screen. Like when the FDR crashes and all is filled with dust - it's there. When you're taking samples from the crashed alien ship everything is fine, but as soon as that area is filled with dust - it's there. It was most noticable to me in the mission with the rain - the rain combined with the night-setting and the grain was almost unbearable... but the game's so addictive, I couldn't stop playing.

It definitely is a bug in the game and it seems to be connected to the savegames as well, but how I cannot tell.
I've had quite a few bug encounters so far to be honest. There were a few bugs that destroyed the game for me, like problems with repeating sound-effects. In the mission after the bridge, you're manning a machine-gun on a vehicle. The nanosuit's motion tracker (I think it was that) went crazy! It seemed to repeat itself again and again and even sped up and got louder after I reloaded the game... I had to turn off the sound-effects volume and played only with music and voice. Luckily, after the vehicle ride it was gone.
There was another repeating sound-effect bug in the hive-level. I think it's been the sound-effect of the Cloak transition... or a part of it... that was repeated over and over and almost drove me mad. It was gone when the next level loaded.
Another bug completely freezed my Xbox. Black screen, no menu, no dashboard would work. It happened after I tried 'Lab Rat' on Veteran difficulty. After I died the game loaded, I hit A to finalize loading and I was left with a black screen and had to turn off my XBox. Resuming the game wouldn't work because after pressing A it was the same black screen all over again. My savegame was screwed. Really annoying. Had to load the mission seperately from the Replay Mission menu, that worked, yet I lost all my weapon-attachments and I might have lost my progress on Veteran difficulty too.
I'm sorry to say that the game appears to be quite buggy. Apart from the problems mentioned there are the obvious problems with the AI, which lets enemies do weird, weird things at times. It's not that frequent though and is actually quite funny. I'm only wondering what other bugs are in the game that I (we) haven't come across yet.
Other than that - the game is beautiful. It's everything I hoped for and more. The single-player campaign must be one of my favorite of all the FPS I played, and there's been a few. Amazing work Crytek, now please just get rid of those bugs and I'm all happy.

Edit: XBox 360 Pro (fat) connected to a Samsung 52" HDTV via HDMI