Gain doodads to interact with larger objects and expand your playfield to gain more doodads.
The game's charm and presentation isn't on Katamari's level, but it's fun to play and it's very full-featured.
edit: I'd actually say it's more comparable in structure than it is in WACKY JAPPY theme. The story isn't anything that jappy. It's actually total dog shit, but there's nothing jappy about it. It's about two busy parents who ignore their kid and shit, I don't think that's a very Japanese theme.