This is a simple game called “Roll Up.” Think Katamari Damacy, Bubbles, Feeding Frenzy, Flow, and any of those other “eat to get bigger” games. You play as a guy pushing a ball around, rolling it over things to make it bigger. You can only roll over things that are smaller than your ball. The fire button charges up a roll-attack, and when released, the player will dash in the direction held.
The purpose of the game is to get the highest score in the time limit.