The best Batman game.
The gameplay clearly can't be upgraded, it's smooth, intuitive and not-so-easy at an higher level (New Game+). Same observation about the graphics, with the Unreal Engine 3 at its best. Strangely I encountered problems on DX11 (low fps, freezes sometimes) with a Sapphire HD 7770 OC Edition Vapor X, but nothing with a Nvidia Geforce GTX Titan. AMD drivers or power of the card? I don't know, but it can be a little irritating, even if the DX9 version is impressive. Finally, the story... The main "quest" is immersive, but what I liked more were the secondary missions, the objectives, and even the riddler challenges! A lot and a lot content: incredible.
I've played 42 hours and I don't get bored at all. 10/10, because not only is it the best batman game ever, but also the best action/adventure game of this generation. Batman: AC surpassed everything that could be done with the genre. A must-have.