While my first impulse is to just say this is "more Arkham Aslyum", it really has improved and polished the formula from the first game. Combat and predator encounters are still a joy (with a few improvements), but the more open environment really showcases the various traversal abilities. Zipping and soaring around Arkham City feels so cool, and doing it well requires a surprising amount of technique. Taken together, it means pretty much everything you are doing is fun, with no obvious "chores".

The main weakness I found with the game was that it just had too much stuff: too many combo moves, too many gadgets, too many riddler puzzles everywhere you look, too many playable characters. There were so many gadgets that on multiple occasions I got stuck in some traversal section because I just didn't remember all the gadget capabilities I had at my disposal. Having put maybe 25 hours into it I'm still not fully comfortable using each of the combo moves (and remembering their inputs). I eventually learned to just tune out the Riddler puzzles, instead of trying to figure out whether I just wasn't getting it or wasn't equipped to complete it (this was much more fun to go back to after the main story, and I did collect maybe a third of them). Once you really get into the game you can start appreciating these things, but I found it frustrating most of the time.