This new film makes it look like he's still like 80% organic, whereas the original was probably just a brain, the front of his skull along with what's left of his face and probably a spinal cord. Also, the original made a big thing of him slowly reclaiming his lost humanity--that's half the point of the story--but here it looks like it's the other way around. As in he starts out himself but finds the machine is gradually taking over.
There is no spinal cord
The face has also been debated back and forth as just as lab created one too.
So brain and probably just a heart.
I always took it he was, essentially, a brain inside a robot that they just plastered his face onto. That's why he needs such meager nutritional intake he only needs to maintain his brain and some skin. At the very most all he is is a skull/head. Otherwise his entire body is robotic.