Doom II: Hell on Earth is about to turn 24 years old, which makes it about great-grandparent age in videogame years. But over all that time, nobody has been able to figure out one final Secret that has taunted players from the score screen on map 15, Industrial Zone. No one, that is, until now. Id co-founder John Romero announced on Instagram that a YouTuber who goes by Zero Master discovered how to activate the last of Industrial Zone’s ten secret areas. Doom map-makers and hackers have known where it is for ages, but nobody until now has worked out how to activate it without using cheats. The secret is triggered by an invisible teleporter that lies in a niche just off some stairs in Industrial Zone. However, walking over the teleporter doesn’t trigger it, and so you can’t activate the secret. The trick, as Zero Master demonstrates below, is to have an enemy - such as your friendly neighborhood Pain Elemental - push you onto it. The teleporter activates and the secret is collected.