I modded the Halo 2 Campaign so every single enemy is the Final Boss, Tartarus. I had to mod out his invincibility shield because it was bugged, but otherwise it's just me trying to beat Halo 2 with a million monkeys hitting me with hammers.

Steam Workshop Download: https://steamcommunity.com/sharedfiles/filedetails/?id=3243085942
Nexus Mods Download: https://www.nexusmods.com/halothemasterchiefcollection/mods/2520