I'm doing the list thing now.
Retro1-1/2/3 is Sky Pup. (Forest Light World, Warp 1)
Retro2-1/2/3 is Space Boy. (Forest Dark World)
Retro3-1/2/3 is Kontra. (Salt Factory Dark World)
Retro4-1/2/3 is Brimstone (Hell Light World, Warp 1)
Retro5-1/2/3 is Skyscraper (Rapture Light World, Warp 1)
Retro6-1/2/3 is Sunshine Island (Rapture Light World, Warp 3)
Retro7-1/2/3 is Meat Is Death (Rapture Dark World)
And for whatever reason, you can't load any other warp zones after that... Unless you have to skip ahead to 15 or something...
And yeah, I've tried it, F12 doesn't work.
EDIT: (character spoilers ahead) If you type in ogmo1/2/3 it loads Ogmo's warp zone :O I'm trying to figure out the others now (I'm 99% sure that Commander Video's warp zone is not loadable. I've tried commandervideo, cv, cvideo, video, commander, and many more, and it doesn't load. Jill1/2/3 doesn't work, Flywrench1/2/3 doesn't, and Kid1/2/3 doesn't work. [also for the kid I've tried many combinations also, and they don't work... It's sad...])
EDIT2: This mike guy (

) and Devon Wargod have informed me about access to Jill and The Kid's warp zones. okay im gonna stop talking like that now... So you use Jill1-1/2/3 for Jill's and Kid1-1/2/3 for The Kid's. Fly1-1/2/3 is supposed to work for Flywrench's but for whatever reason it doesn't work. Still trying to figure out Commander Video's though.
EDIT2.5: Oh, so Flywrench's is just Fly1/2/3. ...WTF!?
EDIT2.5.5: I just tried Com1-1 as an abbreviation for Commander Video, it didn't work. I tried Com1 and the editor crashed. Is that a sign..?