Here is the full list of all 20 Flame Keeper achievements.
Run 10000 units
Regenerate 1000 health with energy balls
Kill 100 enemies with your punch
Find 2 negative effects
Kill each of the 3 species of monsters with your punch
Kill 100 mobs
Finish 2 levels having at least 60% health
Kill 100 mobs having less then 25% health points
Kill 50 mobs with a glory kill
Complete 1 stage without hitting any monster
Use dash to take off energy from 100 trees
Use Dash ability 100 times
Collect 500 energy balls
Eat 30 mushrooms
Fill 3 fireplaces having at least 70% health
Complete 2 missions in survival mode without losing energy
Fall 10 times from an island
Take 1000 damage from monsters
Die 1 times from wind
Fill 30 fireplaces