The story was good! The side missions weren't worth it. The open world was confusing and disorienting.

User Rating: 6 | Batman: Arkham City (Game of the Year Edition) MAC
The open world was very small, but that was not the worst part, the worst part is that it is a very confusing, disorienting, garbage-looking, everything-looks-the-same kind of world. And there are all these RIDLER trophies that you need to collect, I believe there are about 500 of them! WASTE OF TIME, there is no point on collecting all of them. OK, there are some nice ridles to solve here and there but most of them are frustrating and pointless. Don't solve them, who cares...?
Besides all that, the story missions are very good and worth playing, mainly because they TAKE PLACE INSIDE the buildings and not on the open world. The fighting is good and you upgrade quickly acquiring lots of gadgets and new moves, you hardly ever use the new moves but ok... The BEST thing is the stealth action, there are a lot of places to hide and takeout your enemies, it's not easy taking out all the enemies without noticing you but if you plan your attack beforehand you can actually make it.
Play the side missions and/or the dlcs before finishing the main story, eitherwise you will get bored playing them afterwards...