After I did lots of research in sound formats, archives, models and animations I finally decided to get to most complicated task I've heard of: Megatextures.
This is current state of research: Doom/Evil Within/Wolfenstein tools are available here: http://aviacreations.com/wraith/#
And that's how it all started back in march'2017: after a couple of weeks I was able to reverse the modified version of HDP they used and decompress tiles. The devs improved the coding algorithm in compare to standard HDP.
Now I see that tiles are actually in correct order inside of megatexture as expected. This is just a random set of tiles taken from the middle of Wolfenstein Old Blood .pages file. I combined them manually, wanted to check the result as soon as possible

