God of War Ascension by far.
Not only is the multiplayer completely unbalanced, unnecessary, glitchy, and not fun to play, the multiplayer component may have taken development resources from the campaign. I've played all the God of War games and none of them had the numerous game breaking glitches that were present in Ascension's campaign. Thankfully, Ascension's multiplayer is all but dead with nobody playing it.
Maybe Ascension's problems were a factor in Todd Papy recently leaving Sony Santa Monica.