Here is the full list of all 27 Nickelodeon: Kart Racers achievements worth 1,000 gamerscore.
Unlock every upgrade in the store.
Co-operative special attack for the first time.
Compete 10 times in each Arena mode.
Win all Cups in Expert mode.
Win 9 victory laps.
Win all Cups in Normal mode.
Win at the last second in Grand Prix Mode.
Break 5 objects in a single race using boost.
Win with all racers.
Play as each racer at least once.
Use custom power ups for all the racers.
Win a Cup in Expert mode.
Compete in the Arena for the first time.
Take down at least 3 opponents in a single race.
Win a Cup in Normal mode.
Put in the miles on the jetski.
Find a shortcut.
Activate the Slime in all the locations.
Win all Cups in easy mode.
Modify your kart for the first time.
Win a Cup in easy mode.
Win a victory lap.
Beat your record for first time.
Win your first race.
Use boost for the first time.
Activate the Slime valve for the first time.
Use a custom power up for the first time.