This is a really special little game to be made in 72 hours. The music really sets the whole mood and feel of the game...that of some kind of surreal realm where a meditating person struggles eternally to create while an omnipresent force seeks to unmake everything. That he takes the raindrops and turns them into energy to fuel his power to create is so cool, and I really like how there a semi time stopping effect when it's activated and his eyes turn red. The way you can hit the cloud to force it higher, changing its patterns as it fights back harder is so satisfying; each strike feels like an achievement!
I sincerely hope you expand upon this someday, because it could be quite amazing. I want to see this go somewhere as I haven't gotten this sort of feeling about one of these challenge games since Cannabalt years ago.
The only reason I didn't give this a 5 is that it's a bit frustrating getting stuck under your own creations and because the view doesn't let you see where you are dropping things if a spot gets lowered too far.
In the event you do work on this game more, I'd suggest expanding on the man's powers, such as letting him stop time midair to create things, and having a way to teleport back above your created pieces. If you could work in an upgrade system where excess power stored beyond the limit lets you improve your powers and building/piece durability and other interesting things I think it could really go somewhere. Heck, maybe even a scary factor where after a certain point the firey abyss below you begins to consume your structures from below.
In any case, great job! You managed to pull a review out of me, and that alone says something about your skills!