I think that an actual motion capture could make the animations (only for human characters obviously...) a lot better, this is what I think about the humanoid characters in-game:
1)
Class-Ds: they really need some better animations; yeah, there are more important things to focus on but I really think that some of Class-Ds ones (particularry the
standing animation or the falling animation that plays when they get killed by SCP-173 in the intro) really need some tweaks...
2)
Scientists: they are pretty much fine, maybe you could give the scientist that walks at a door in the intro a less "gangster" feel like
Irontaco and
Omniary said (maybe he could hold a clipboard and look at a document on it while he's walking to the door?). The scientist that runs away from SCP-106 has pretty nice movements.
3)
Guards/MTFs: it looks like they have wooden legs...

Making their leg movements more natural is the only real problem with them (I think that they should bend them while walking...) And I think that the guard in the event with SCP-096 should have a running animation when he actually runs (not "walks"...) away from SCP-096...
4)
SCP-096: the only problem here is the "angering" animation: he should shake like a crazy dude, in the game he looks more like he's having a very strong headcache...

Other that that he's pretty much fine... (maybe even his run could be more "crazy" but that's not so important since the actual one is pretty good. And I think that he should really use some of the new animations made by Night...
https://www.youtube.com/watch?v=GnonwQz0Ddc )
5)
SCP-049: he is pretty much fine, I don't think that there is so much to do with him that could involve the use of new animations...
6)
SCP-049-1: except for their really strange way of attacking the player, in my opinion the zombies are the best-animated characters in the game.
7)
SCP-513-1: he's fine in-game, probably we could improve it somehow but what kind of movements should he do?