I'm on chapter 3 or 4 now, and having a blast. Love the Zero-G stuff.
Inventory management was a pain, and I kept getting ammo for guns I wasn't carrying and hadn't even bought from the store. So I found myself backtracking to the last store quite often so I could sell off extra ammo and buy the type I actually need. But now I got the hacker suit and it's not so much a problem.
I'm liking the multiplayer too. I enjoyed it when I was in the beta, but wasn't sure about if it would really feel needed with the full game. It's no "needed", but it gives me a vibe similar to horde mode in Gears. Though an actual horde mode would be even better (or let me and some friends play the human side of a MP match against bots only, but with no time limit and more necros). At first it felt like the humans were overpowered, because I did terrible as a necro and dominated as a human, in the same games. But after a few more games it seems more balanced, though the humans can still get terribly spawn trapped by some coordinated necros, which was a problem in the beta too.