The split screen idea is neat, but I'm not seeing what function it actually serves from a gameplay perspective. Looks very gimmicky atm.
I would say that having x-ray vision to help solve puzzles instead of the split-screen. Is a missed opportunity in this video. Hopefully that materialises more in other sections.
Also, it seems like changing from one world to another is game determined, and so far looks like it happens as like a 'cutscene'. I don't know how else to explain it but clearly you lose control of the character when it transitions (this is seeable in the original trailer too).
So, a cool concept but nothing about this video sells me on this game unfortunately.