Well well well.
Even after being told how good it was (on the xbox) I didn't actually think it would be that much fun!
Stealthy fighting actually works which is surprising, having not seen a game do this satisfactorally for years (Deus Ex was the last one I remember). You're not constantly thinking "bleh, that should have worked!" because whatever you want to do, does!
It's probably the best batman game I've played since the one on the spectrum many, many, many years ago (almost 20 years?) But then again it's the only Batman game I've really heard of since then.
The combat system felt very much like the one used in Beyond Good and Evil, in fact it feels like they took a lot from that game in terms of stealth too. But the big thing about it is using the grapple to hide in the rafters, which really is rather fun.
It's not absolutely perfect, there were a couple of times when I'd hit one member of a group with a bat boomerang thing, I then went to hide on another gargoyle. Once he'd got up they all inexplicably looked at me as if to say "Why did you do that?" and then went back to looking down a coridoor. Strangeness.
Anyway I really do recommend trying out the demo if you've not already! You can get it on steam by clicking this link