Here is the full list of all 38 Skilltree Saga achievements.
Login 20 times
Defeat 25 Orc Scouts.
Defeat 10 Orc Scouts.
Defeat 25 Orc Wolves
Login 10 times
Defeat 3 Orc Scouts.
Learn 10 Skills
Defeat 50 enemies without dying or fleeing
Defeat 10 Orc Wolves
Defeat 25 Goblin scouts
Defeat 10 Frost Wolves
Defeat 25 bosses
Defeat 3 Orc Wolves
Loot 5000 ducats from defeated enemies
Defeat 10 Goblin scouts
Defeat 3 Goblin scouts
Defeat 200 enemies
Loot 2500 ducats from defeated enemies
Defeat 10 bosses
Defeat 25 enemies without dying or fleeing
Defeat 3 Frost Wolves
Loot 1000 ducats from defeated enemies
Defeat 100 enemies
Defeat 5 bosses
Login for the first time
Defeat 10 Mosquitos
Defeat 50 enemies
Defeat 2 bosses
Defeat 10 Forest Mushrooms
Loot 250 ducats from defeated enemies
Defeat 10 enemies without dying or fleeing
Learn 3 Skills
Defeat 3 Mosquitos
Defeat 10 enemies
Defeat 3 Forest Mushrooms
Defeat 75 enemies without dying or fleeing
Learn 20 Skills
Defeat 100 enemies without dying or fleeing