Going Down is hard for me to review because of how unique it is despite being just another Boom compatible megawad. Plenty of megawads exist that have unique themes and brutal open ended levels but Going Down sets itself apart through intelligent use of Boom actions. No two maps feel exactly the same because under the hood they always have something different going on. Walls falling to reveal a new hellish underside, a dark mirrored version of our world, rooms that transform faster than you can blink an eye, and a literal descent into the mouths of hell are just a few of the things Going Down does to stay fresh. Go play it and you will not regret it.
Took me a whole 40 minutes to finish, perhaps I'm just slow, but this map in UV is pretty tough, complete with Doomkid's charm and his custom monsters, definitely does what it sets out to do pretty well.
I couldn't find the ssg and indeed it makes the thing quite hard, wasn't a fan of the final fight either, but overall, very fun to go through.