Sorry I can't give a more relevant response, but it plays beautifully on my iPad Air 2 and iPad mini 3. #
Seriously though, I am of the opinion that it will be absolutely fine, given that things like GTA 4, Civ 5, and DOTA 2 have been shown to be perfectly playable on the machine. Since Bastion is a top down isometric view game, and it isn't exactly cutting edge in the graphics department, it should be fine.
But I don't have mine yet so can't give you a real experience answer.