I can't remember the name but it might be dino park or something similar. Basically a rip off of Zoo Tycoon but with dinosaurs and it was awful. Outdated technology at the time of release bad graphics etc.
That was the first thing that popped into my head. 1-3 were good, the rest suck.
I think the worst game that I've played that isn't in the new Rachet and Clank series is this Spongebob game my little brother made me buy for him on his B-Day. Its so DUMB I spent like $30 on it because it was new. The cut-scenes were stupid, the jokes weren't even jokes AT ALL, and ALL the characters either smiled, looked mad, or looked just plain weird ALL THE TIME!!! If Spongebob was supposed to be sad he was still SMILING that was how bad it was.
oblivion. maybe it´s not that bad but everyone "forced" me to buy this game because it´s the best game ever made and i played it like an hour and i got a headache so bad, i think my brain wanted to punish me for spending money on this crap.