I think it's an okay game. It's a Splinter Cell rip-off that's too easy (but this could just be the demo's difficulty), has some stylish "Batman" moves, and a slow-moving/too easy, but competent fighting system.
My favorite thing right now is fighting with a grapple point nearby. While on top of a gargoyle, I used the grappling hook to bring a guy up to me, then Batman hit him and sent him flying back down, with a rope around his feet. Him dangling there brought more guards to check it out, and I jumped down to take one out, then was able to grapple back UP to the gargoyle to avoid the other's gunfire. THAT was cool.
So I like the sneaking stuff/stealth take-downs (reminds me of Tenchu 4), but am kind of "eh" on the combat, due to its simplicity and slow moving fights. Hopefully you aren't forced into combat sequences with no way to escape like in the beginning of the demo.