Here is the full list of all 15 Biglands: A Game Made By Kids achievements.
Fully Upgrade All Weapons
Die 300 times
Beat the Game
Beat Humanya Ka,olana
Beat the Graveyard
Jump 10000 times
Fully Upgrade Any Weapon
Attack 10000 times
Kill 2000 monsters
Collect 7000 items
Beat Dr. Evil Herobrine's Lab
Beat Twilight Forest
Beat Mars
Beat Cloud Island
Beat Lava Land