Well, mirages, that's for sure. It sorta looks like the oasis is actually the water tower (juxtaposition of Dreameg sitting over the edge of the tower and the edge of the oasis), except both vanish at the end, so probably not.
If the water tower and oasis are mirages that occur during the day, then I guess Dreameg has to console the guy through the night, because when the mirages disappear, he realizes they're lost in the desert without any (real) food or water.
(Also, that equates the night with death, and that one always works!)
The figure getting up and having a cord attach to its head near the end intrigues me. Umbilical cord? WHAT OF THE BABIES??
The whole thing with the colorless dreamworld (which lends extra meaning to "the outlines have been lost," since it's ONLY outlines), Dreameg standing on top of the masses of machinery at the end, and fading to white then suddenly black makes me think Qualia prequel.
She doesn't look much like Qualia, though. (But similar eye markings, as if that means anything.)
On the topic, maybe their dreams are colorless because all they see awake is desert? Man, that would be getting even more into the concept of qualia than Qualia does.
In fact, in a (somewhat meta) way, "no stories" could represent not knowing about anything better/not having anything to look forward to like the WEU couple did.
Similarly, "nowhere to be" implies they have no so-called "surface of the umbrella" where they "belong." (And the babies? Man, I don't know.)
Dreameg most likely has memories of whatever better place they came from and believes they'll be back someday (though she has to convince the guy it's not hopeless). Having those memories and that hope is why she would talk about flowers despite being in a desert.
This is also why Dreameg would want the guy to talk about his own memories, however vague they might be. They are incapable of keeping silent. It's so they won't think. </godot>
Anyway, the ending could pretty easily be happy or not. While she seems to be standing atop all the (mechanical-looking) dreams as if she'd conquered them, the song seems to end a note early and cut to black, so perhaps now she has to deal with them.
I'm not sure it works quite as well in the original Japanese (where it's literally "my chest hurts"), but it would be somewhat ironic that his crying "pains her inside" if eating his dreams to prevent such tears hurts her too. Well, eating that eye thing looked pretty gross in the first place.
Ignoring all the specifics, it's really just a nice song about a girl sacrificing herself for her partner, in an almost-motherly way (lots of people say it sounds like a more-upbeat lullaby), to get through hard times.
For reading all that, have a somewhat poetic comment (kinda like the WEU one) from a piece of Pixiv fanart, of all places.
"There need be no words between her and I. We are joined. We share our painful times together. Because today, somewhere, flowers are blooming."