I had a lot of fun with the shareware episode of Blake Stone back in the day.
I revisited it a couple of years ago and… hoo boy! It is way harder than I remember!
I think it is a worthy member of the Wolf3D engine family though. It’s fairly slick and well put together. There’s some really cool enemies and weapons, and a few nice extra gameplay elements, such as automap and money, as well as ceiling and floor textures.
One of the big things I remember is that they did not waste any space on the maps – every empty space was usually crammed with secret areas.
Another game based on the engine was the notorious “depth dwellers”.
Never played it, but I’ve definitely heard… things about it.
Of course, the Wolf3D engine is actually an improved version of the Catacomb 3D engine, which itself is an improved version of the Hovertank 3D engine, so I guess those games deserve a mention as well.