I voted other because it is generally a mix of all of the above, but the strongest case against a game would be fucked up mechanics. And that doesn't always kill it because they can lead to some funny moments, but some mechanics can kill a game and make it simply unplayable.
Story won't kill it, but it will certainly make a game less enjoyable and make me not want to stick around until the end as much
Unclear instructions have been the case for some games where I pick it up and assume it's going to be a certain way because of genre or because it belongs to a series... then I find out it is way different and I can't figure out why they changed it or how they changed it soon enough for me to enjoy the game
Voice acting... um... I guess not really a problem. I think lack of voice acting would get boring fast though. Maybe part of the reason Zelda games put me to sleep.
Difficulty usually isn't an issue because they can be adjusted. I do hate how you can't adjust difficulty mid-game (like in L4D) because maybe I'm finding the current level too easy and want to switch it up, but the game won't let me. Kinda lame on that end.
Graphics, like voice acting, usually not an issue. However, I can't stand the N64 graphics anymore. For some reason I just get headaches from the damn thing. I don't play Golden Eye or like it simply because of that.