I've finished the main game; a satisfying ending, though it felt a bit quick as a wrap-up. Great game, wonderful reboot of a beloved, iconic character. My final percentage at completion was 97%, so I have now cleaned up the loose ends to 100% completion. Theoretically I need to go kneecap a few more dudes, and pull a few more off from ledges, and I'll be quit of it.
I'm not going for the "had every conversation with every Survivor" Secret Achievement which I didn't know about until 2/3rds through the campaign. I hate those things. I think I hated it more in the original Assassins Creed, where I actually tried for it, and STILL have no idea where I missed one.
Multiplayer, I've got a couple more things I want to get from it, but I'm not going to go for utter completion. If I'm going to get into multiplayer, I'm going to go back to Max Payne 3, which is similar, but better, more fully populated, and polished.