Don't be alarmed by the Japanese text! Click 'start' and then click on the camel for 1, 2, 3, or more players (technically, all modes are 'one-player,' you are just selecting how many characters you will control at once.).
Katamari Damacy is by Keita Takahashi, ©2003-2009 NAMCO BANDAI Games Inc. This online version is hosted at CurrentLab for educational purposes.