The writing. If a review says that the story and characters are good but the gameplay is not, I will go for it and play it through, probably more than once. (Dreamfall, I am looking at you.) The one thing that will break me in a game is bad inventory management. I popped open the Morrowind inventory screen and after five minutes I was clawing at my face with visual frustration. I've never cleared the starting area on that game because the minute I started acquiring loot I wanted to put my head through the screen.