Here is the full list of all 21 Red's Kingdom achievements.
You've completed the game.
You've completed the game without dying.
Complete game under 90 minutes
Get the medallion
Get the Wing Suit
Get the Glowing Mushroom
Collect 100 Nuts
Collect 500 Nuts
Collect 1000 Nuts
Have 5 Hearts
Have 8 Hearts
Find a collectable
Find 5 collectables
Find all Collectables
Get 100% Progress
Find the Golden Nut on Solas Cala
Find the Eagal Island Map
Get 120% Progress
Find the Golden Nut in The Golden Nut.
Lock the Golden Nuts in your vault.
Get 150% Progress.