The original Tomb Raider had no open world, but yes, that Uncharted 4 demo gave me a slight but distinct Tomb Raider look and feel. Not a bad thing IMHO, as it's not a cut and paste, but just a similar feel, and if it's true it's open world, that's a thing that was completely absent in the original and best first TR titles, so the game should be quite different. And TR arrived not to open-world, but to a large hub-based world quite late, so even UC4 openness can't be considered a TR rip-off.