Here is the full list of all 28 Nickelodeon Kart Racers (EU) trophies - there are 10 bronze, 11 silver, 6 gold and 1 platinum.
Unlock every trophy.
Unlock every upgrade in the store.
Win all Cups in Expert mode.
Win 9 victory laps.
Win a Cup in Expert mode.
Win all Cups in Normal mode.
Compete 10 times in each Arena mode.
Compete in the Arena for the first time.
Win a Cup in Normal mode.
Win with all racers.
Play as each racer at least once.
Use custom power ups for all the racers.
Win all Cups in easy mode.
Put in the miles on the jetski.
Activate the Slime in all the locations.
Win at the last second in Grand Prix Mode.
Co-operative special attack for the first time.
Break 5 objects in a single race using boost.
Modify your kart for the first time.
Win a Cup in easy mode.
Win a victory lap.
Find a shortcut.
Take down at least 3 opponents in a single race.
Beat your record for first time.
Use boost for the first time.
Win your first race.
Activate the Slime valve for the first time.
Use a custom power up for the first time.