Doodle Drift is a 3-lap arcade racer where the actual skill being tested isn't top speed, it's how cleanly you slide through corners. Holding the drift button through a turn builds a Drift Score meter in real time, and that score converts into Drift Coins once you finish -- roughly one coin per 10 points of accumulated drift score.
Those coins spend in the Garage on four rides with genuinely different handling, not just reskins: the free Starter Kart is balanced, the Turbo Wedge trades grip for a higher top speed, the Night Racer leans the other way with better grip and quicker acceleration at the cost of top speed, and the Golden Drifter is the fastest but loosest of the four. Picking a kart is really picking a driving style, since a high-grip car and a high-speed car reward different cornering habits.
A car's grip stat directly affects how easy it is to hold a drift on purpose -- the Golden Drifter's low grip makes it slide into drift more readily (great for score-chasing) while the Night Racer's higher grip makes it more forgiving for clean, fast laps. If you're racing for coins rather than lap time, it's usually worth deliberately oversteering corners you could've taken clean, since drift score adds up faster than the small time penalty costs you.
Coins come from your Drift Score, which builds while you're actively drifting through corners, not from lap time or finishing position. Roughly every 10 points of accumulated drift score converts into 1 Drift Coin once the race finishes.
Each has distinct top speed, acceleration, and grip values -- the Starter Kart is balanced, the Turbo Wedge trades grip for top speed, the Night Racer trades top speed for better grip and acceleration, and the Golden Drifter is fastest but has the least grip, making it easiest to slide into long drifts.
Drifting isn't required to finish the 3 laps, but it's the only way to earn Drift Coins for the Garage -- a race won purely on straight-line speed finishes fine but banks very little toward unlocking new cars.