A lot of people are starting to run into this new game-breaking bug in Borderlands 2. There is already a 27+ page stickied thread in the official 360 Borderlands 2 forums alone (http://forums.gearboxsoftware.com/showthread.php?t=150907 ), but it is affecting all platforms.

Essentially, the autosave feature begins to slow the game after each save until it freezes completely, forcing a hard-reset. The bug gets progressively worse until the game freezes at the press start page (this is what happened to me and quite a few others), at which point the title screen can no longer be accessed in any way. Gearbox has yet to offer any real response to those affected by the bug, which is disheartening, as it renders the game completely unplayable and seems to be affecting more players each day.

To me it happened when I am level 27 Axton going back to do the Arena battle which I saved for when I was OP but after activating the quest the game freezes on the start or loading screen every time!

There is a temporary solution involving the use of a USB thumb drive, but many have said that even this method begins to freeze upon saving the game and does not work at all for me:

https://www.youtube.com/watch?v=OxYKOozfNQ8

So are any other duders having the same problem?

No issue at all. I did have ONE freeze but it was during a timed quest when I had about 50 things shooting at me and explosions going off all over the place. 

I've had the game freeze once (on PS3) and I have characters at levels 50, 23, 15 and 8.

Zero issues here so far, and I just recently beat the final boss on my second playthrough. Hope it's sorted out for you folks. :(

@Cincaid: Thank you, me too:(

This is happening to me. I have severaly days played in-game (on X360) across all 5 characters. I use cloud-saves, but I don't think that's relevant given what I'm reading in the gearbox post.

Game played absolutely fine since it came out, then last night it froze up on me whenever it hit an autosave. Now it freezes during cutscenes, if I'm able to even play at all.

The gearbox post mentions filtering/sorting the missions, which I've never done. Can't wait for a fix. C'mon MS, cert that shit.

Mine started about a week ago.. now I cant play it... I thought it was the disc at 1st till today.. Thx for the info now i have to wait for a patch..