Here is the full list of all 17 Mobmania achievements.
Defeat Witch.
Complete the tutorial.
Defeat 100 Mobs.
Defeat 1000 Mobs.
Defeat 2500 Mobs.
Defeat 5000 Mobs.
Defeat 10000 Mobs.
Defeat 50000 Mobs.
Play a game.
Win on one character.
Win on five characters.
Win on ten characters.
Wing a game with the Jester trinket equipped.
Defeat Ninja.
Complete a daily challenge.