DRD Team

Thanks for looking into it.
I was able to reach one of the creators on youtube, but he still hasn't replied me back. According to one of his comments, the engine was some sort of Wolf3d engine clone, which is already different enough.
The non-orthogonal walls exhibit corners on the map. The doors in the game resemble the ones from Corridor 7 a lot. The floor and ceiling shading look like the ones used in Planet Strike. Like Wolfenstein 3D, There is also 4 weapons, 1 with infinite "ammo", but another is for blocking only and each one uses its own ammo. The movement seems similar to ROTT, only without bobbing. It uses .PCX images.

Doesn't seem likely. Looking at some videos the walls are clearly non-orthogonal, the physics look to be a bit different, basically none of the strings in the exe match. Which of course doesn't necessarily mean anything, but if they were going to rewrite that much, it would be a waste of money to license the engine imo. There are at least two middlewares involved though: "RiverSoft Data Library" and "WORX TOOLKIT VERSION 2.1" from Mystic Software.

I don't know if anyone here is familiar with this game. I wonder if it's based on the Wolf3d engine and if it is, is there a chance of it getting supported in ECWolf. The company who made it (Coresoft) probably doesn't exist anymore and is distinct from the current Coresoft as it was founded in 1998 and the game is from 1995.