Here is the full list of all 24 Tropical Demo achievements.
Ride a manta
Ride a turtle
Talk with duck
Try to open locker 3188
Drink rainbow
Win a football match with Marlene
Try every waterslide in Tropical
Find swearing parrot
Click on every minigolf stage
Try to enter the garage during the nightmare
Click on one of the purple-blue parrots flying nearby the disco
Crash scooter into all of the characters
Click on the passage leading to nowhere
Click on watermelon
Talk with Marlene about the Tropical sequel
Slide on a tray on Lagoon waterslides
Offer starfish a beer
Click on pizzeria during the nightmare
Click on frogs enough times so that Dominica decides to try her old style
Wake up Adele so many times she'll get angry
Finish the race in 120 seconds or faster
Make Jacob win the race
Finish the first day in Tropical