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