Just about finished with my first run through as Corvo and I'm pretty impressed overall. Lots of small things that bother me though :
-Went from a simple yet very effective interface to this bulky, unnecessarily complicated mess of an interface
-The sound of footsteps don't seem to really correlate to where the other people are... I'm wearing my headphones and I hear footsteps only in my left ear, but there is nobody there, and there is absolutely somebody on my right
-It feels quite a bit more linear as most windows are locked, most rooftops are inaccessible due to height, and it really cuts down on the use of going vertical to bypass obstacles.
-When you get a new bonecharm it just goes somewhere in the list, so if you miss the name of it when you picked it up, you have to scroll through the whole list and try to find the new one. Also, the bonecharm list appears to have no sorting AT ALL, makes it's frustrating to change them around for certain encounters.
Overall it's a badass game and I think it's a very good sequel, small quirks aside, it has quite a bit or replay value due two main playable characters, as well as going high chaos, med/low chaos, non-lethal ghost. I've taken my time and really tried to find every bonecharm/rune, as well as every painting, and I think I'm about 15 hours in just as I'm starting the last level. I would say that if you liked the first one this is going to feel great and it's a welcome addition to my library.
Edit: I did mean to comment on a few of the levels and their complexity. Two levels in particular feel almost like Legend of Zelda dungeons with how they are designed. One is a mansion level where there's switches which rotate and alter the rooms, forcing you to really put it all together mentally to get where you want to go. The other is a time-traveling (only 3 years) level which requires you to go back and forth in time to get through the map. Pretty amazing and lots of fun, much more than I had expected from the trailers.