This question will never, ever be satisfactorily answered, because even high flown are critics and writers can't agree on a definition of what "art" is.
Personally, I choose to ignore this question, and instead ask not is this game art, but where is the art in this game? For example I recently played Ni No Kuni and though I really don't know if I could call the whole thing art, certainly some of cutscenes (especially the Studio Ghibli ones) and other aspects of the presentation, like the score qualify in my opinion. Rather than ask such a wide and possibly unanswerable question, why not simply look at the parts and not the whole, for that way things can be even more inspiring and artistic (IMHO,of course)







