The title comes from the file name, but Dan Froelich explained that the file names were in fact the proper full titles.
Jill of the Jungle: Jill Goes Underground (DOS)
In second game of the series Dungo is only played in "Montezuma's Castle" (levels 3, 4, 5, 6, 7 and 8).
The file in the game folder is named DUNGO.DDT.
Onesimus: A Quest for Freedom (DOS)
In Onesimus Dungo is played in "The Desert" (level 6; identical to the first level of Jill of the Jungle), "The Vista" (level 20; identical to the final level of Jill of the Jungle) and "The Hut" (level 22; identical to the bonus level of Jill of the Jungle).
The file in the game folder is named SONG4.ARK.