It's the first time in my console-player life that I see something like this.

I'm in a level where I get attacked by a helicopter through big windows.

EVERYTIME I turn on my PS3 and load the game, it glitches after 2 secondes. And it glitches very hard: no any button work, I have to turn it off by pushing on the console.

BUT the MULTIPLAYER does work indeed. So it is not a BR or Console Problem. It's totally a GAME GLITCH.

Does anyone has already had it before? I'm pissed, I thought that these kind of glitches only occured in PC: There is something happening in the game at the moment of the loading that makes it glitch. And of course... as usual... the saves are AUTOMATIC, so I can't have made several saves as I usually do in case of...

This is so screwed. The game is unfinished to a point where an automatic save ruins the campaign game forever.

You can can always restart that chapter. Main menu select campaign then select the last one you were on and go from there. This way you can continue to play.