Hunter and I downloaded this demo today and played with it for a good hour!! This game is SO fun!! Some of the enjoyable elements include:
A fun fighting mechanic where you use X for agression and triangle for counter-attack defensive moves. So if you see an opponent (they surround Batman often) about to attack, you can counter!
Battarang...just a lot of fun to knock someone down from a distance!
Glide/Kick - Nice way to take someone down from afar
Ground/Takedown - Once you knock someone down, you leap on them and knock them out with a special move.
Silent Takedown: - Much like Metal Gear, it's refreshing to sneak up behind someone and suffocate them until they pass out.