Despite the browns and grays that are prominent in this megaWAD, I found it to be fun. I also found it to be quite the challenge. The first map gives you a taste of what to expect in terms of enemy encounters. The author makes good use of mid-tier enemies to apply pressure on the player. Monster count for most of the maps barely breaks the 150 mark but, as said before, the use of mostly mid-tier enemies puts pressure on the player. I also like how the megaWAD handles level progression. Most of the levels you go through consist of caves, cities, islands, and tech bases in space. In fact, there's only one real Hell-like level and even it's within the confines of the moon base you fight through in maps 21 - 30.
About the only gripes I have with this megaWAD are with regards to maps 32, 29, and 30. I know the text file and map 31 give warnings about map 32 but there really should be some kind of alternate exit in map 32 instead of trapping you in place if you don't pass one of the puzzles. I wasn't a fan of how close quarters the IoS fight was in map 29, especially since it can get cramped quickly with monster spawns. Finally, the randomization of what keys spawn during your escape in map 30 isn't fun either. 10 minutes seems like plenty of time but between navigating the vent system (again) without light goggles and dealing with mid-tier enemies, that 10 minutes can get eaten up really quick.
Overall, it's still a fun megaWAD. I'd recommend at least giving it a shot.