For me art is something that makes you feel something differently or shows you how to feel something you never experienced. It's something that teaches us about ourselves in ways not limited to the restrictions of modern life.
If you can play a game and the game makes you think about something, then it was art. If a game gives an emotional connection which was beyond the story or the visuals. If it takes you somewhere and shows you something you didn't expect.
My problem with the Games as art thing is that Games seem to be transient. They will not survive individually to be recognised or appreciated as art later on. Games need technology to play them and as technology advances, it leaves old games behind.
Old paintings can be stored and displayed in museums for all to see.
Games need a bit more than that. Advances in paper did not make canvas obsolete or prevent it from being seen.
Here are a few games which have made me think... mostly about the human condition.
Mass Effect - We are insignificant in the universe and no matter how far we feel we have advanced, we are as barbaric as ever. With all of the improvements in technology, we still choose to be shitty to each-other, greedy and violent. We have not outgrown our base instincts to survive and grow at all costs. We know this and hide behind a thin veneer of civility But as Commander Shepherd, you can choose to do something different, to be a force for good and try to make a difference. To buy humanity more time so that we may grow up a little.
Mah-jong & Bejewelled - Life starts out pretty easy with seemingly unlimited choices, but with each choice you find that you limit yourself in some way and have to suffer the consequence. If you're lucky, you'll clear the table and win. Most of the time though, your choices just take you down a path where there is no return. We cannot see the future, We are not in control of our destiny, we just have to play the game with the options we see and hope for the best.
Mario - A jong journey faced with countless dangers. You can be as prepared as you like but in the end, every choice you make could be your last. Rescuing the princess is always in the back of your mind driving you onwards but before then there is the journey.
Oblivion - Walking in the countryside, I see places I want to explore, I can almost smell the forest. I am alive. I am free. I stumble upon a wild animal who turns to fight me. The animal slain, I see ancient ruins and consider what kind of civilisation was here before me? Even though I am powerful, beings greater than myself have been lost and their structures lie in ruins. What fate for me then?
Or maybe, Games aren't art and I just need to get some therapy..