For me the visual qualities of the game are not too important. However if the game looks good it's even better. The most important thing in a game for me is gameplay. It's hard to identify what exactly it is. Simply said, if the game process is interesting for me, it's ok.

Another thing I really value in games, but most of them lack is atmosphere. If the game makes me believe in what is happening on the screen, it can rouse some emotions, feelings in me, it is great. One of the main reasons why I like games like System Shock, Thief, Deus Ex is that they have a great atmosphere. You fear of every sound, you're very careful, you're trying to hide in shadows. Oh, well, after playing System Shock 2 for two nights, I've been trying to reach my shotgun every time I heard the monkey cry.

Another things that are important for me in games are story and setting. When a story is good in a game, the experience from it may be much better then after watching a good movie. The characters in a game are very important too.

It's good if a game is non-linear, it has many variations of how you can go through it. However a game with a straight plot can be good too. I also don't like when a game makes me rush the decisions, I hate timelimits. I prefer to have an option of carefully thinking my next move and plan ahead. So, I don't like the real-time in complex games like strategy games. Real-time with a pause option is perfect for me though. For action games pure real-time is fine of course