So I've played through all of it and have changed my opinion somewhat. Overall, I think KDIZD feels like a showcase - it's very pretty and is an amazing show of graphical and interactive features, but it doesn't play well, it fails to improve upon the original levels in meaningful ways and ironically, it doesn't have much of Doom's atmosphere. The gameplay of the original levels is smooth, fast and easy to follow, but now it's confusing and filled with backtracking and whilst the intermission screen is really fancy, honestly the original 2D pixel art looks more appealing. Loads of locked doors have been inserted everywhere which painfully draws out game time.

In addition, many of the additional areas feel arbitrary and unnecessary and many of the new monsters stick out due to unthematic placement. Too much artistic license has been taken with the original source material to the extent where rooms no longer resemble the original ones at all. Top notch visuals & intro and the interactive features/intermission screen are both good, but the maps are too large and end up being labyrinthian (sadly the camera screens don't help much because of this).

Doom knee deep in the dead secrets