I gave a test and it's quite nice, though i had to turn the quality down so the blurry tone would disappear as it was hurting my eyes.
It's easier to get the hang of the controls than i thought, after resetting the key to ones you prefer of course, but the tutorial is buggy, couldn't move more than the "how to reload/recharge" part in which the "go to green warp to end" does nothing anymore.
The only low point in my opinion is the artistic choice of "toon-ified" characters and titans, the manga design is making the atmosphere rather grim and oppressive but in that game the funny look of everyone is unfortunately not making that atmosphere right even when you've got a titan that catch you and eat you.
But in term of gameplay, it's rather polished. Tough i wish you could set the camera to TPS once and for all in the options as each further game it revert to that original camera thing that isn't really playable or even fun.
Didn't tried multiplayer but on single play it's getting a bit boring after a while as it's really missing some AI soldiers in the humanity side to make the fights more "alive", so i guess it's probably shining much more in multiplay.
I gave a try to using the Eren Titan but then it was way too easy, kick small titans is insta-kill them, punch 3 times a titan and his head explode, so it's recommended to play one of the soldiers instead for having some challenge.
On my best attempt, i managed to kill 2 titans but got crushed by the 3rd one i tried to attack after a missed strike that had me landing in his arm unfortunately