I'm loving the game, but it does have quite a few bugs, mostly minor. Freezing during loading, the hud showing in the middle of the screen, AI enemies that are sometimes there, but not 'alive' (just stand there, and not killable), and so on. My only true complaint right now is that I use the arrow keys, and you cannot bind Enter, which is always used by me for 'action' like open. Fixed via keyboard software and key switching.
The game feels like a combination of the first and Invisible War. While the hubs so far can be large, they have all been rat-maze type maps - haven't seen anything remotely as large as the first map from the original. But, the feeling of those areas definately feels like the first game.
I haven't sat up all night playing a game in ages, but played til 5AM this morning. The game really is fun.