John Romero has just congratulated Doom guru Zero Master on discovering the last hidden secret of Doom II, some 24 years after it was released. A secret that had previously been thought impossible to actually find.
Prepare to put your Doom Pedantry Hat on for this one, because the secret has been known, and considered a bug.
"It is normally impossible to register secret #4, as the secret sector in question (sector 147) is located adjacent to the raised teleport pad and is only 16 units wide. This setup completely prevents the player from touching this sector's floor (as is required to trigger a secret), because upon crossing the sector's boundary they are immediately raised onto the pad and teleport away. Therefore, the maximum SECRETS percentage one can ordinarily get on this map is 90%."
Unless it turns out, you get pushed into it by a demon. Jump to 3 mins in the video below to see the rather uneventful moment occur:
Zero Master explained why the bug meant it was considered impossible saying, "In other words, a secret can only be triggered if doomguys center is within the secret area and if he is on the same height as the secret sector. The second being impossible because doomguy is always lifted up to the teleporter floor height when his center is either exactly on or over the secret sector." But, it turns out, tricking a pain elemental into helping you out gets around this. ZM continues,
"This trick has something to do with the moving door and the pain elemental spawning a lost soul on top of you. This forces you down to the lowest floor the moving door is on, which puts you within the secret sector and on the same height, thus triggering the secret."
Doom's co-creator John Romero took to Twitter to congratulate Zero Master on this saying,
Secret explained: A secret teleporter is marked as a discoverable "secret", but when you touch it, you never enter the sector. So you would never get inside the teleporter sector to trigger the secret. The only way to trigger this secret is to be pushed by an enemy into it! #doom— 𝕵𝖔𝖍𝖓 𝕽𝖔𝖒𝖊𝖗𝖔 (@romero) August 31, 2018
So there it is. Just shy of 24 years since the game was released, finally all the secrets have been successfully discovered without the use of noclip. An incredibly niche thing to be sure, but you know, it's testament to the absolutely pivotal importance of Doom to all of PC gaming history, that it took three decades to see the game possible to 100%.