I just had an idea for a classic doom speedrun challenge,
Noclip%
You have to be in noclip mode at all times and can only use idkfa for weapons in the boss battles that require you to kill the boss (you also can deactivate noclip at the end of episode 1 where you have to use the Death teleporter to end the episode)
Since you're in noclip, you can't grab any pickups, so all damage is permanent, and you can't grab power ups, also no weapons (until you have to use idkfa for bosses because killing them with a pistol and not dying is incredibly challenging if not virtually impossible given you'll eventually run out of ammo and have to punch the fucking cyberdemon)