No monsters mode
Several bugs are present with no monsters mode. On some levels, such as in the boss maps of Doom and in MAP32: Grosse of Doom II, monsters are a necessity for exiting. Also, the Icon of Sin's monster spawner is ignored by the -nomonsters parameter. When a level with a lone spawner and Romero's head is completed, each kill aside from the head adds 100% to the kill percentage.