There's no engine in these karts. The hill does the accelerating, so the only question is how much speed you're willing to keep when the next corner shows up.
You can drift them, and it feels great when it works. It also goes wrong a lot. The back end steps out, the kart spins, and quite often the driver keeps going without it. Getting thrown out isn't a game over. You get up, walk back and hop in again.
A normal race is only one of the eight game modes.
In Avalanche a giant boulder comes down the road behind the whole field, and it doesn't slow down for corners. In Trick Run the finish line matters a lot less than your score, so you spend the way down drifting, jumping and collecting points for anything that looks impressive. In Chained Together you're physically attached to another player, which means their mistakes are now your mistakes too. More game modes are coming soon.
Turn items on and the racing gets a lot less honest. Oil slicks, a sack of flour in the face, a wall dropped across the road, a goat. An actual goat.
There are also 25 mutators you can switch on before the race, like low gravity, inverted steering, bouncy karts or helium voices. And if you can't decide, there's Chaos mode, which throws a random mutator into the race every 30 seconds until nobody has any idea what's happening anymore.
If you're going to be launched off a mountain, look good doing it.
Paint your kart panel by panel, cover it in stickers, write whatever suits you best, and bolt on accessories that won't survive the first corner. Your driver gets the same treatment, so everyone knows exactly who just took them out.