Here is the full list of all 31 The Adventure Pals achievements. It takes around 10-12 hours to unlock all of the achievements on Windows.
Collect 10 cupcakes
Use a Weapon Mod
Use the Cupcake Converter
Complete your first objective
Level up your abilities for the first time
Vanquish 10 enemies
Collect first cupcake
Get your first pal
Make it to second island
You've used nine lives but don't give up
Kill 20 yaks on world map
Defeat treefist
Defeat Breakfast Buccaneer
Defeat Veggiesaur
Defeat Crab mech
Defeat Hot Dog Boss
start a co-op game
complete a stage in less than 3 minutes
Give the whale the old mans underwear
Release 50 old people from hotdogs
Defeat all the arenas
Kill an enemy that's been converted to a bunny
Find 50% of the stickers
Beat an arena
giraffe-copter for 5 minutes in total
kill 100 enemies by jumping on their heads
Fill up your sticker book
Get all achievements
Unlock all costumes
Fully Level Up
Finish the Game