I am interested in games as an art form. But a lot of these "artistic" darlings strike me as pretentious drivel. To me, Portal was much more successful than Bioshock as an art piece. It wasn't dancing around trying to tell me how important it is.
I also happen to think the mechanics of a shooter can be art.
I also think that. The problem is that most people focus on the "meaning", "emotion", "philosofical" aspect when making these "art games". That mostly involves the game's story and narrative, and that is only a subset of game design/development.
I consider something artistic when it displays the creator's mastery of the craft. So yeah, Portal is art. Dear Esther? Pretentious drivel, without a doubt!
If you want a great art game, that was made to BE an art game and is not a deep philosofical piece try The Marriage [1]. This game actually disturbed me, as I considered Rod Humble to have achieved IT, to have created the first PURE videogame. Give it a try.
I also happen to think the mechanics of a shooter can be art.