I know the version we are seeing in the Beta is an unfinished version from months ago but I just wanted to post my thoughts on what will hopefully be more polished about the 4 man kill sequence in the final release.
The blood -
The blood pouring from the wounds looks pretty good but it still doesn't look quite as good at the blood from GoW III. I know the effects team was working on redoing how the blood looks/behaves for Ascension so this is probably due to an influx blood particle system.
Starting with III the team made the blood more realistic looking and therefore darker red but I still feel, in the bright daylight setting of the Desert of Lost Souls, the blood looks a bit too dark maroon. Maybe add some specular maps to the blood (if possible) so that in the light you can see the red show through a bit more during daytime settings. I remember the blood in GoW III being dark but in the scenes where it made sense to be brighter and more red it looked great.
The biggest grievance with the blood is that it doesn't stain Polyphemus' face. GoW III did an excellent job of showing wear and tear on the creatures Kratos brutally killed and you could see where you had damaged them really well. (Examples: seeing where you stabbed the lion body of the Chimera, seeing the entry wound when you stabbed the goat head with its own horn and the cuts you would make on the cyclops when climbing him etc...).
When you break his jaw and destroy his eye there is no blood to be seen anywhere on Polyphemus' face. There should definitely be blood all over his face because he rears his head back in agony when the spear is first stabbed into his face. It looks odd for such a brutal kill to not leave any trace of blood on the victim.
The breaking of his jaw -
Now his jaw breaking is truly brutal but it still lacks the oomph other brutal kills in the GoW series have had.
The spear stays in his jaw with light shining off of it which looks really good. However, when the jaw finally gives away and breaks, it just kind of opens as if it was a door ajar. There's no sense of weight or the pressure it took to break such a massive jawbone.
I feel there should be a blast of energy from the spear right as the jaw breaks. This would sell the jaw breaking open more and the spear could get blasted back into the ground instead of just falling back to the ground, making the whole scene more visceral and brutal. And the spear causing an explosion that pushes the jaw wide open would also be a good way to hide the spear disappearing when finishing Polyphemus without winning the match.
Eyeball Stab -
The eyeball stab looks pretty brutal as is but the best part of it is the segment leading up to the actual stab.
Seeing the eye throb as the hooks strain against it is very well done but once the spear is stabbed into the eye the attention to detail and polished nature of the kill ends there.
The eyeball just turning all red makes it look like it was cheaply textured because the team wasn't sure what should happen once the eye is stabbed.
Maybe the energy that remains with the eyeball could blow up bigger and brighter and send some sort of shockwave out as the eye explodes with chunks of the eye and optic nerve getting blown out of it instead of just the basic particle blood effects that are present currently.
Hopefully the kill sequence will be as polished as the single player kills when the game is finally released.