Wow. Wow, wow, wow! I love this! So much effort put into it, so much creativity. This is really a work with soul. It's not just something you made to look like you're so deep or whatever.
It's got a good sense of humor, but it's also got a really interesting reality-bending story that isn't spoonfed to the viewer. Now, my guess is, in regards to the meaning, that this guy is imagining all of this as he's dying, reliving his last moments, at the end realizing the fact he's dead. This comes from the flower guy's "monologue" showing him phasing through a door and getting chopped in half and the repeated transitions through his head. Versions of him that have been chopped in half are also pretty common in the movie. The thing that confuses me is the ever-growing building.
The animation is amazing, I love the textures. Sometimes it feels like a more conventional but well animated cartoon, other times it's a little Gilliam-esque. The sounds are also incredibly ambient and serve the story well.
Keep it up, I've followed you already!