Here is the full list of all 31 Kingdom Eighties achievements. It takes around 15-20 hours to unlock all of the achievements on Windows.
Complete the game in 50 days or less
Complete the game on Hard
Complete the game on Cursed
Survive for 50 days in one level
Destroy a portal on Peaceful
Slap a monster truck
Complete a level with no more than 20 kids
Uncredited professional BMX rider making it rain coins
Defeat 10 greed with a machine gun
Lose the Crown, and take it back
Complete Episode IV
Get something back from the past
Destroy a portal around the mall
Rainy day at Paradise Estate with Rainbows in tow
Complete Episode III
Complete a level with only two workers
Get eaten by a shark
Destroy a portal on the streets
Complete Episode II
Lose 80 coins to the waters
Recruit someone smart
Recruit someone friendly
Complete Episode I
Clear all the trees on any level
Enter a cave
Wait for the bus
Destroy another portal
Destroy a portal in a forest
Recruit someone handy
Recruit someone athletic
Find the missing trophy