Here is the full list of all 29 Slipstream achievements. It takes around 12-15 hours to unlock all of the achievements on Windows.
Defeat Norman in Parthenon.
Defeat Alex in Metropolis.
Defeat Tofu Boy in Akagiyama.
Complete everything.
Defeat Camilla in Highgate Cemetery.
Win a cannonball race of all 5 secret tracks, in any order
Win a cannonball race of all 5 nighttime tracks, in any order.
Defeat David in Neon City.
Win a cannonball race of 15 tracks.
Complete all possible routes in Arcade Mode.
Defeat every rival character in Arcade Mode at least once.
Win a race in Grand Prix mode without any car upgrades.
Reach every exit defeating all the rivals along the way.
Complete a stage in arcade mode without touching anything.
Win a cannonball race of 5 or more tracks.
Win the Diamond Cup.
Win all the races in all cups.
Win the Emerald Cup.
Get to all the exits in Arcade Mode.
Win a battle royale match.
Win the Sapphire Cup.
Win all the races in any cup.
Win a race with every car model in Quick Race Mode.
Defeat all the rivals in a cannonball race of 5 or more tracks.
Visit all the tracks in Arcade Mode.
Defeat all the rivals in a single Arcade Mode run.
Win the Ruby Cup.
Stay on the slipstream for more than 15 seconds in any mode.
Get to the finish line in Arcade Mode.