I'm pretty disappointed with this. One unpaid intern could have done this in a week. A day if using pre-built UE4 assets.
With so many millions spent and so many years in development I'd really expect much better, even in a pre-alpha.
I personally would probably not have shared this video. Even ignoring the really low poly models & textures which I'm assuming are part of the low poly client (and standard affair in this stage of development), even the animations are really clunky, and the animation transitions.
I'd probably reserve demos like this for alpha backers, and put up real client more polished stuff for everyone else. Otherwise it'll just inevitably hurt the brand. Alpha backers do need to see stuff like this to provide feedback though. That is, alpha backers that actually understand their purpose in an alpha. And I'd label it like asset testing rather than showing off progress.
Okay let me go through this like I'm in an alpha trying to find stuff that could/should be improved:
I'll start with animations.
The walking, which we see up to 10 seconds into the video. It's just weird. Especially how the arms are held out in front of the character like they're carrying a package just wobbling side to side. The run itself is pretty flat footed and I'd say almost waddling.
The transition coming off from the ladder that we see at around 18 seconds is super janky and needs corrected.
The sliding, I'd probably add a few variations because it is it seems a bit odd, and pretty stiff.
The jumping animations are okay, but they're a bit too casual looking for what the character's doing. Almost like playing hopscotch or something rather than jumping from platforms. The back being stiff and largely uninvolved probably plays a huge part in this. The whole body should be involved. Like movement with the arms, a bent torso, and some full body movement looking like the body is actually vaulting rather than just a casual skip.
The handrail sliding thing was okay with the rope. Could probably look into variations of the animation with more momentum added that look more athletic.
I'd probably add a few different fall variations, because falling on your face every time could get a bit silly.
The jump at 1:24 seems a bit weird. I'd say almost sort of a side-jump animation? It needs some work as well, like the other standard jump animation.
The balancing bit seems a bit too stiff. I'd probably look at variations in that, especially with characters that have a stat for acrobatic stuff. So the ones with worse in it would be more shaky and wobbly but ones with more would be more solid and do it more easily to the point that it's like Altair in Assassin's Creed just running across a tight rope.
The jumping from the grid thing at 2:24 needs a bit of work. And the way the legs & stuff are behaving overall on the grid thing could also use a bit of looking at.
The weird slump after jumping to the land after the grid thing could use some improvement. Like, not doing that.
The mid air roll thing at 2:40-ish is real janky, and its transitions.
At 2:53 or so, jumping from one ceiling log thing to another, it is sooo janky. Then jumping to the platform after that, the animation/pose is just really ... in need of improvement.
The jump at 3:03 is just weird. Like someone skipping.
The weird jankiness on the log that follows up to around 3:09 also needs to be looked at.
Then jumping to the log which lands at 3:10 is just really really bad. You can also see more of the super jankiness on the log around 3:17 and around there. And really we have that terrible jump to another log after that again at like 3:22 which is almost like a t-pose in the jump.
The transitions leading up to 3:28 really need looked at.
The animations for the wall running/jumping at the end also need modified a bit to put a bit more weight & energy behind them.
I won't comment on the other stuff for now, but that should be a good start.