A great game is one that...
1. Doesn't treat me like a
ing retard. When I say that I mean no checkpoints every 5 seconds, no regenerating health (well to a point, I mean not the CoD of GoW style of I regenerate all my health in 5 seconds after standing in cover), one that actually rewards me for using strategy effectly.
2. A world/story that one can really get into. Something that is not generic story of the day. It's unique, and has it's own sense of style. Plus not this generic ok I am the good guy, in the end evil guy dies, you win. A story that really hits home that yeah while it may be fighting the evil guy, but it just wasn't so clearcut.
3. Feeling of control. When I say that, I mean when I play the game I should feel like I am in control of the character, not just do what the developers planned for me to do. I am not talking like games need to be open choices like Mass Effect, but more so I feel like it just isn't about things like hiding in cover 24/7, it's more of play how I want to play the game (and not how the developers want me to play it).