In the Doom game's story, the UAC's over - ambitious research on Mars goes terribly wrong. Their exploration of teleportation technology leads to the connection with Hell. As a result, the base is overrun by demons. The player, as a space marine, has to fight back. The levels are filled with intense combat situations. You encounter different demon species, each with their own abilities and weaknesses. The story unfolds as you progress through the levels, facing more and more powerful demonic threats, all while trying to find a way to close the portal to Hell and save humanity.
Doom novels often feature a desolate setting. For example, in 'The Road', the landscape is barren and filled with ruins. They also usually have a sense of hopelessness. The characters in these novels may struggle against overwhelming odds, like in 'The Stand' where the survivors face a world full of death and destruction. Another characteristic is the presence of a threat, whether it's a natural disaster, a tyrannical regime or a technological nightmare.
The length of the Doom story can vary depending on how you play and explore. But typically, it's not super long and can be completed in a decent amount of time.
The length of the Doom story can vary depending on how you measure it. If you consider just the main game storyline, it's not overly long but still engaging.
In my opinion, the story of Doom Eternal is quite good. It has an interesting plot, intense action sequences, and well-developed characters that keep you hooked throughout the game.