I don't see anything that would suggest it looking like Kamacura or Ebirah. There is no body, no eyes, no full view of the hands/claws/arms, nothing.
How some of you can speculate that it looks like a Toho monster is beyond me. Seriously, just leave Toho's monsters alone. They're not in this movie. Never have been. Never will be. Regardless of what the MUTO creatures final forms are, they won't look all that much, if anything, like Toho creatures.
Next, the MUTO is most certainly NOT coming from the right.
Looking at the top of the train I see nothing to the right except the background of the shot and a fritzing piece of metal and wire from the train. No shadows, no body parts, nothing. The attack is coming from the left side, and this is proven by the fact that it is moving forward to start (slighty towards the right) and then recoils back (to the left). If it were coming from the right, the laws of nature and the laws of physics both would require it to recoil to the right side where the body would be, but that's not what's happening is it?
It's a nice image to give us an idea of what the MUTO skin texture and coloration is, but beyond that this image tells us absolutely nothing. Again, there's no clear view of any individual body parts to tell us exactly what's happening, so we're just going to have to make due with the fact that the train is being cut up by something and that we have no idea what it is or what it's doing.
