The most devastating bugs/glitches

[HardkorSB]

Have you ever encountered a bug in a game that was so big, it actively prevented you from progressing in a game? Were their also any bugs which caused you to stop playing because they were so infuriating?

I remember a game for the PC in the late 90's. Sadly, I forgot the title but it was a horror mystery type of game, where you were trying to uncover some conspiracy and prevent a zombie outbreak.
It was pretty fun BUT the game crashed... ALWAYS. I thought I just got a bad copy but no. All of them crashed. There was a review in one magazine which tackled this problem. The reviewer apparently tried about 20 different copies and they all crashed in the exact same spot.
Wish I could remember the title.

 

[AntiChri5]

New Vegas.

During the main quest, you are forced into a bulding. The only door out locks, and does not unlock until you finish the quest. For one of my characters, some flag didn't get set because that damn door never got told to unlock. There is no other way out, no other way to unlock it.

Another character has a bug where The Strip (the centre of the city which the game's plot revolves around) refused to load, making the game unfinishable.

Seriously, fuck New Vegas.

 

[Beautiful End]

Sonic 06. The Game Grumps can explain this one better than me but let's just say that game is filled with tiny, little bugs and glitches that can screw you over randomly when you least expect it.

Personally, Grand Theft auto 3. I remember I was trying to complete the game 100% and I was succeeding. Then I was asked to kill a bunch of gang members with a drive by. Turns out, that file was glitched or something and it made the gang members not exist, basically. Funny because other files had the gang members but unluckily, not THAT game file. And this was back then when games had no patches or updates. So my choices were: keep going and not get the 100% or start all over. 2/3 into the game.

So I ditched the game.