Memento Mori is a megawad for Doom II made in 1995 by many different level designers. The soundtrack was made by Mark Klem and is included in the zip file as a standalone .wad file called MMMUS.wad.
Mark Klem made many midis for Doom projects back in the 1990’s including such notable releases as Requiem, Memento Mori II, Strain and Gothic DM.
Samples:
Listen to Galaxy by Mark Klem
Listen to Hidden Anger by Mark Klem
Source: https://doomwiki.org/wiki/Memento_Mori
Download: https://www.doomworld.com/idgames/themes/mm/mminfoup
Memento Mori! What a great memory. Loved the Text Screen song.
Agree! Mark Klem made some excellent tracks back in the day!