Ever since I stumbled over Noesis the other year, it amazes me how much effort has been put in to this game. By using the program, it has allowed me to find things you wouldn't usually be able to see. I have no idea if we already have a thread like this somewhere (I tried searching), but it would be cool if we posted anything interesting here.
Here's just some of the things that have been pointed out before:
ROM-0 28.DAT: This big secret zone has no name, but there's an entrance to a town, which looks like it may be a reference to an early trailer. There are signposts here, one of them pointing to the "Chocobo Wood", and another pointing to the wood and "Sel Phiner". This is likely the name of the town, or an early name for Selbina, but who knows?
The coolest thing is a railway system with an upside down train. There's even detail inside, so perhaps we were meant to ride like we do the airships or boats. Across the map, there's a place showing a rusty section of track which is broken and placed over a canyon. Maybe there was an earthquake and it had to be left? It's clear this area was made very early in the games development. SE abandoned it and has done nothing with it since.
ROM-0 40.DAT: The big blue & white checkboard area is known as a GM area. Maybe someone can find a video, I can't remember where it is.
BCNM areas: SE uses several (usually three) of the exact same area miles away from each other to allow more than one party to enter battlefields.
In ROM-0 74.DAT, the three floating Throne Rooms away from the main spires have detail for a whole entrance outside of the battlefield, despite never being able to see it.
It's likely they originally intended you to zone in down the steps and make your way through another door to reach your battle, in a similar way you run up in other areas. Instead, you zone straight in to the room in front of your targets. They probably thought we'd already done enough running, and I can't blame them.
In ROM-1 6.DAT, the mountain range you can see after exiting from a Horlais Peak battlefield is HUGE! It's bigger than the three battle areas combined. SE were excessive, they would have got the same effect if it were half the size.
ROM-0 79.DAT: In the North section of Windurst Waters, you can see a low detail Heaven's Tower slightly away from the boundary. While it gives you the impression of its size, it's far too close compared to where it actually is in Windurst Walls.
ROM-1 4.DAT: FFXI has a prison area called "Mordion Gaol". It's a small area similar to the entry in Legion. They have 32 copies of Mordion Gaol, so there's plenty of room to keep people detained.
ROM-1 5.DAT: This strange little area is for the login screen. You can find little houses here, made up of three small villages, but you will never see them while logging in as you can't look around.
ROM-1 12.DAT: I was often told that the Legion zone shares an area with Ambuscade, but this DAT shows the five areas on their own. I'll have to find an Ambuscade zone first, though.
ROM-1 20-22, 45-47.DAT: There are small corridor's outside Mog House's with details for stairs and the other side of the door, like you were originally meant to walk through it to get to your Rent-A-Room.
ROM-1 24, 25, 29, 30.DAT: Shows the maps used for the boat trip between Selbina and Mhaura. Why are there four identical zones? Perhaps dependent on the type of ride you experience? I can't remember if there are two boats. If so, there are two zones for each.
ROM-1 26-28.DAT: The World Maps for airship rides are not very detailed and largely inaccurate, but you can spot some landmarks. For some reason, the airship begins in the floor, but you'll never notice because it rises up before the screen fades out.
ROM-1 48-127.DAT: There are many town areas which don't automatically load the interiors of buildings in one DAT, and instead bring in others for more detail. Most of the ROM2's are like this as well.
ROM-3 2.DAT: The first character model is an Orcish Overlord wielding a staff. I'm trying to remember where this comes from. Is it a NM or part of a cutscene? It's certainly not Overlord Bakgodek or a regular Orcish Overlord.
ROM-3 47.DAT: Either my memory sucks or I have never encountered this baby Soulflayer NPC before. What is it from?
ROM-4 67.DAT: A scantily clad Mithra playing around with a pot in very mysterious ways. This is one of the strangest things I have found.
ROM-5 67.DAT: A red Orcish Warmachine. Looks pretty cool! But I can't remember seeing it anywhere.
ROM-6 32-53.DAT: The line of Fomors have some really disturbing animations. Solid nightmare material.
ROM-7 80+81.DAT: Shadow Lord!
ROM-159 81.DAT: Bahamut!
That will do for now. If anyone has found anything interesting, please let us know!