Awful dialogue
Plotholes in storyline
Poor characterization
Confusing instructions
Unnecessary information
Many of these, I can live with. Awful Dialogue can be charming, ala Resident Evil 1 (which is probably the exception to the rule, come to think of it). As long as the plot doesn't have holes so big you can coast a Death Star through, even that's fine. As for confusing instructions? Well, I play Eve Online.... and moving on.
Unnecessary information is boarderline, since it's really subjective what's unnecessary. On the one hand, it could be world building. There was a lot that came out of the Metal Gear Solid games, but they weren't all necessary.
I where went with Poor Characterization. All the rest could be well and good. I find recent JRPGs do this; The world will be laid out, and it will be stunning. The concepts and plot direction are all there, with enough slack in them to not really give the impression of a strong plot hole. NPCs from all over are all worthy of nothing but intern voice actors and one offs trying to make it big. It's all there, tollerable, and then the camera settles on the main cast....
Lo, and behold, for it is Cookie Cutter roles! Archetype "Lead Character" is atypical lead material, with mannerisms liken to that of 15 different (but all very same characters at the same time) other leads that use the same hair spike gel. And his best friend, a girl, that could very well be his sister, or he'll at least call "big sis" because she acts like one. She'll scold him, because he is supposed to grow up. He's a man now (reading the manual bio at this point would show that he's just turned 15, or some junk), and needs to start acting like one. Then his best friend, who is younger, and looks up to Generic Lead. This characters gender doesn't matter, ultimately. It's spineless, whatever gender may be overlain here.
And that's just a start. If you've played JRPGs, I'm sure you'll find I'm not far off the mark. A few adjustments to the cookie cutter, and you go from ginger bread man to cactus, but it's still a cookie cutter with all the same ingredients.
I can't play these games anymore, thanks to these tropes. I find it hard to even enjoy anime now, because these character tropes are not exclusive to video games. I used to LOVE anime... then I started to feel like I've seen these characters all somewhere before.
Anyway, bad characterization goes a long way for destroying a game experience for me.