Part of Doom Eternal · Doom Eternal: The Ancient Gods - Part Two
The Ancient Gods picks up after the end of the main story in a time where, due to the Slayer's actions, the armies of heaven and hell have fallen out of balance. The demons have flooded in to overtake the weakened angelic realm, so the Slayer's been called in to clean up the mess.
Verdict
<1week
You'll breeze through this one.
A meaningful commitment beyond rolling credits.