I haven't played many games after NES was outdated (still play the one my parents got my sister and I in '89), so my opinion is lame, so I'll tell you the worst game ever...
Teenage Mutant Ninja Turtles...I spent years of my life not getting anywhere playing that game (okay, not years, but I don't want to know...I basically quit video games after getting so frustrated with it and I even gave it a go like 5 years ago). I do play Techmo Super Bowl on occasion, though and actually bought a game a while ago when my cousin lived with me and had an XBox...MK vs DCU. Goodness, I'm getting old.
Hmm, maybe I should play DOOM again.