I agree with Keith, and I feel like it would be easier to give crits if I knew what you were going for. For example, the shape of it's head kind of bothers me, but that might just be a stylistic choice. He looks kind of happy and surprised in the two newer ones, where he looked slightly angry in the original. The two tentacles that are (hopefully, unless im reading it wrong) pointing at the player are hard to read and kind of look like tumors on the two tentacles that they're in the middle of.
You have something crazy going on with your shading but I think it comes out looking really cool and your dithering is great, I just don't really understand what the octopus is supposed to be doing. Is he going for a hug or is he trying to be threatening?