While it's a shame to see someone risking legal issues to present their work (not sure what the law is in Argentina, but graffiti is a bit of a legal issue up here in the US) it is good to see it conveying a positive, hopeful message (something that's sadly absent in most of the graffiti in the US).
The scale of the project is impressive, and its color and message stand out in stark contrast to the surroundings. Based on what graffiti is normally seen around my area, this is certainly an original approach to it.
The character is on-model, and the clouds are a nice touch, but it would have been nice to see the swirl technique replicated from the show. The work turned out quite well, especially considering there was a storm that interrupted you.
Overall, it's a solid, inspirational work of art.
@ Legal issues: The way it looks to me, most of the spots chosen for graffiti are sort of no man's lands, if it's similar to Hungary's point of view... State owned walls, bridges, etc that can easily stand a coat of paint / nice piece of art as the state surely won't touch it.
Yeah, I suppose being from the US, or at least my part of it puts a different context to it. I really do love the effect of sprucing up an otherwise barren wall. Actually, it'd be a nice change for some of the ones around here that are currently covered in graffiti of the less-pleasant sort. Art or not, it's still someone else's property and they might see it differently.
Basically, I'd love to see more, but I'd hate to see someone get busted for creating some pretty neat stuff.