Maybe something like "Going Deeper" for the top screen, assuming that the first time you enter that screen you do it from the top and have to drop down. Or if you aren't against names that are overly obvious you could try "Tunnel of Traps".
The middle one could possibly be "The Lonely Bones" or something like that. I noticed you use the same bones in the next screenshot though so perhaps that name singles out a feature that appears too frequently to use it as the base for your title.
Couldn't for the life of me think of anything for the last one that wasn't overly generic, like "The Lost Storeroom" or similar. Plus I'm afraid that I don't know enough about the game's other screens to determine what I think is the room's 'signature'. Still I hope my suggestions help or at least inspire better ones.
[the following was also posted on the Spuds Quest blog]
Cool, thanks for using my idea!
About the two similar rooms, I think it would be good to know whether or not the skeletons are significant. Are they important objects, or just decoration?
If it's the former, then I think Zanzubar's ideas "Room of Orpheus" and "Room of Eurydice" would be fitting. Otherwise, you could add other objects. I don't know what I would name screen #2, but screen #3 could possibly be called "Stagnant Storeroom"? Perhaps screen #2 could have something added to it, like a bit more vines. Then its name could stem from that; something like "Green Corridor" to match the vines and the green fog. I dunno.
btw, do you still need music? I know a very nice chiptune track "Mosquito" by Purple Motion that I think matches Spuds Quest somewhat nicely.