Personally, the worst bug I've ever encountered was in Metro 2033. Just bought the game, having immense fun, totally immersed in the game... I was riding a rail car, with a ranger. We just got done getting shot up by Nazis, and then we continued on. BUT, at the end of the tunnel, THERE WERE THREE OF THEM WAITING FOR US! My comrade quickly swerved left to avoid them, as I shot at them with my revolver, barely giving them flesh wounds, as we went down the alternate tunnel. It was dark, so I decided to don my NVGs, as we continued on. I saw lots of trains... We were in the Depot. I saw a black figure jumping across above us, so I knew we were in for a fight. Then, AUGH, my HEAD! The stupid creatures were attacking our minds! After a long, hard fight, I ended up skidding along, my comrade dead, the creatures closing in fast...But the cart outran them. I turned around to heave a sigh of relieve...Right as my face smashed into wooden boards. I quickly recovered, and ducked under the next ones, but then...The cart hit...er...something poking out of the ground...And the cart fell on me, as my character exclaimed exactly what I was saying (Nearly simultaneously. Ironic, no?). after I had recovered, crawled out from under, ready to continue traveling...I disappeared. I fell through the game, into nothingness. Several tries, attempting moving, jumping, and crouching, yielded the same results: Complete failure to continue due to a game-breaking bug, that leads to a technical glitch. Damn it, someone needs to make a fix for this. (Or you guys need to lead to one that's already been made, as Google has failed me. (And ironically led me here.))