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