I like to try new genres, so the criterias can change, but for what I call a great game, it needs :
1) A great scenario, and likeable characters. That's the scenario that makes me want to go further in the game.
2) A big replayability, and a large post game for grinding, and get some more infos on the characters etc
3) A lot of random, I like random. I can spend hundreds of hours on random dungeons.
4) Customizable characters is always a plus
For the questions :
Hours depends on the genre, I might say that 60 hours is ridiculous for some games
Visuals : I love nicely animated 2D sprites. But no indie pixel art crap, where it's almost not animated. And the HD and 60 fps is always a plus, if done correctly.
Extras : post game and customization and procedural maps
