Two things come to mind while playing TNT: Evilution, tedious and poorly designed. TNT: Evilution is the second half of Final Doom which also comprised of The Plutonia Experiment, and while it isn't as difficult as Plutonia, it sure is a confusing mess at points. Apparently, this was going to be a free megawad until id Software came and said they wanted the wad to be a part of their Final Doom package. That's why a lot of Doom fans hold a lot of resentment towards this wad, and honestly upon replay I don't blame them. I couldn't imagine paying a whole $60 to play this thing. The level that really highlights how incompetent some of the level design is would be Map 18: Mill, which has one of the more infamous puzzles the wad features. It features four buttons with 3 of them blocked off, and all the buttons lower sections to get a yellow key. Some of the rooms surrounding the buttons have some of the most confusing level design. At no point does it prepare you beforehand for some of the gamplay choices it implements. For example, a shootable wall to raise a lift. I wondered around for about 10 minutes before figuring that out. Then there is baffling design choices like Map 20: Central Processing, where the exit is not a button, but an exit sign that you have to press to exit. One level that remember most from this wad is Map 27: Mount Pain. The titular Mount Pain of the level sparked my imagination back then along with the first two Doom games, it's a shame most of the rest of the level is a tedious slog to get through, with a boring sewer segment to boot. I used to think this was a decent wad back when I first played it, but by revisiting it on a higher difficulty, the cracks really start showing in this wad. It's a shame, too, because there are some interesting concepts this wad tries to implement. It just never fully realizes that potential.