This really does capture the spirit of Katamari Damacy! The pleasant visuals, the dinky sound effects, the underlying dark humour are all well done. Thought the dialogue was a nice touch too, especially how when you get past a certain size it becomes too tiny to read and you're filled with pleasant thoughts about the smallness and futility of humanity!
The scale of the ball is conveyed well through the heavier and heavier inertia, but it would've been nice if you got the wonky rolling from Katamari working, though I can imagine that would be awkward to code. In terms of the overall structure you got the spectacle of building up from a grain of sand to rolling entire islands right, but moment to moment it could've used the Katamari trick of gating progress by confining the player to an area sealed by some roadblock. Felt like there should have been those kind of subgoals that daisy-chain all the way up to consuming the whole town.
Considering Katamari Damacy was made by a whole team of people in a few years and you managed this in a few days, I'm quite impressed!