Doom II wad - Hydrosphere (Map03 and Map04) by Brian Irving

Maps 3 and 4 of Hydrosphere, a 6 level Boom-compatible mapset. Pistol start for both maps.

Played with the GZDoom source port.

Hydrosphere by Brian Irving
https://www.doomworld.com/forum/topic/128979-hydrosphere-6-level-boom-mapset/

GZDoom Source Port
https://zdoom.org/index

Doom II by id Software
https://store.steampowered.com/app/2300/DOOM_II/