Please only post game breaking glitches that include spoilers IF THEY ARE IN A HIDDEN SPOILER TAG.
I will update the OP with the game breaking glitches as you guys post them, I only have one I fully understand so far (but have read many more) so I'll just start with posting that.
- DO NOT enter any casino with a companion currently bound to you. When they take your guns, they also take your companions guns (Even if you tell them to wait outside!) and after you leave and try to give your companion their weapon back, it will be impossible. It will appear in your inventory and you can equip it but you will not be able to trade it/sell it. This will mean that companions like Boone can become completely and permanently useless after this happening.
- hardcoe mode broken. For some reason SLP no longer has a number counting and instead just has the arrow which points to where 0 would be. It never goes up or moves at all.
- Picking up certain item corrupts saves on XBOX360. Minor Item Spoiler.
Spoiler
"Picking up the Space suit in this quest CAN, but not always, corrupt save files on the 360. Does not occur on the PS3 or PC"