Final Fantasy is long enough to have multiples for me. FF2 would be the first for it's awful growth system. FF12 would be next for never going anywhere interesting with the plot, having bland, lifeless characters and stultifying gameplay. FF13 is possibly worse but I wouldn't know because I lost interest too much by that time to finish a game I wasn't particularly enjoying.

Suikoden IV - Completely took away all interesting gameplay aspects of the series with the four member party with pretty run of the mill skills. Terrible plot. Annoying characters. Interminable sailing. Suikoden Tactics gets on this list too, because while the gameplay is better than IV, it doubled down on IV's awful plot with even stupider stuff.

Breath of Fire VI - I mean, I didn't play it, but just look at that trout.

Zelda II - What were they thinking? Even Ocarina at least attempted to make a Zelda like game and wasn't this bad.

Pacman 2: The New Adventures - Oops. Sorry, this game is awesome. I meant all other Pacman games are the black sheep. Why couldn't they be more like their younger brother?