The Wonderful End of the World is basically Katamari Damacy for the PC. You move your avatar around the levels, automatically absorbing objects no larger than you and continually growing in mass so you can absorb bigger things.
The game features some cool levels, like a retro arcade level and an abstract level consisting of nothing but letters and words, but other than that the 12 levels are very similar to those found in the original Katamari Damacy.
The game is pretty short, and I beat it in under 2 hours. If you don't own Katamari Damacy I could recommend a purchase for the End of the World since it's a cheap $10 on Steam, but if you already own its predecessor it's skippable. The demo does have the retro arcade level though, so you can check that out if interested.