Caesar.: It certainly looks very impressive. What I don't understand is -why bother with the Tomb Raider IP? Any indie original project that looks as good as this would get immediate attention in any gaming forum/community, and they wouldn't have to risk being shut down by the legitimate owner.
Probably because he's a huge fan of the TR games. He is using the official sound effects from one or more of the games, and if my eyes are not deceiving me he may be using some of the 3D models and game textures from some of the other games as well, perhaps along with some improvements. There just is not enough publicized information as to what exactly him and others created from scratch and what they reused of the existing game franchise assets.
If you load up Tomb Raider Underworld and do a side by side comparison, there are some clear similarities in models and some graphics though, but his demo looks supremely better graphically using the Unreal 4 engine, so even if they are official game assets, he has made them look better.
Note, this is all speculation based on anecdotal observation and comparison with the official game IP. If anyone has Underworld, I recommend installing and comparing the two side by side, or using screenshots of the two. This demo looks better, but similarities appear to suggest asset reuse (which isn't good nor bad, just an perception that may or may not be correct).
The reason I mention the above however, is that it appears most of his effort has been working with Unreal 4 engine and pulling everything together and reusing some of the original IP to get things out there. If he had to also either create all of the 3D models, textures and other game assets himself as he would if making his own 100% original game, he most likely would not have this demo out there right now.
So I would agree that if 100% of what we see in this demo was all 100% original content, artwork, 3D modeling, sound effects, and all other code and data involved, and none of it re-used any previously copyrighted material, and it only used the Tomb Raider trademarks, characters and look and feel but implemented from scratch - making it as his own original unique game would have been a better decision to turn it into a business of creating a new IP. But it'd take a lot more people with a lot more hours of man power to do that, and it does not appear that that was ever his objective.
Pretty clear that the motivation of this is that of a fan of a game series expressing his love for the game franchise itself as a form of art.