I was actually very pleased with that game. I'm not big on zombies games (except Walking dead and Left for Dead 2), but finally, this one is not so much a zombie game than a parkour game with zombies elements. There were many things I liked, with a few quirks.
- the night/day cycle and all the mechanisms attached. Very good idea, runs at night can be terrifying but they are at the same time so rewarding that you can't resist doing at least some.
- the skill tree : not bad, not bad at all, you can really develop the way you want to play. Of course, if you unlock all, you'll become an unstoppable killing machine, never exhausted, but that was certainly the price to pay.
- the story : yes it's cliche, but at least it's quite well told and you finally care about the characters. That's all i really ask a video game, to be honest
- the maniability : you start clumsy and within a couple of minutes, it's exhilarating to find new ways to use the environnement to move around. Yes, parkour at its finest, Mirror's Edge-level (and that's really a praise!)
- the collectibles : nice touch for the completionists (which I am not)
- the final fight. Come on, it must have been the worst designed boss battle I've ever had to play in a veeeeery long time. The game is about freedom to move, and suddenly, you're just a button pusher. Bad, bad, bad.
- some game design choices, like for example when suddenly you can't use the grapple anymore because it would make that portion of the game too easy. That's a cheap way to deal with the scenario...
But I have had a very good time playing it. I haven't finished all the sidequest, so I will certainly go back at it, preferably in online co-op with a friend.
So far in 2015: http://www.gog.com/forum/general/games_finished_in_2015/post2