So I just a new trailer on the Noclip YouTube channel's newest epsiode on Arkane Studios and its history.

And they'll eventually talk about the canceled HL2: E4, with some never seen gameplay videos and potentional modeling (like one of Father Grigori)... but in my opinion of their interpretation of Father Grigori looks like something out between FakeFactory's Cinematic Mod and Hunt Down The Freeman version of him.