You can earn three Crowns in each level, this is as follows:

1. Clearing the level for the first time
2. Exceeding the par score
3. Finishing under the par time. Every 10 Crowns, you will unlock a new Attack Skin. Attack Skins are just cosmetic and will not affect gameplay.

Hong Tongue - Attack Skin 1:
Collect 70 Crowns

Hong Tongue - Attack Skin 2:
Collect 80 Crowns

Hong Tongue - Attack Skin 3:
Collect 90 Crowns

King Tongue - Attack Skin 1:
Collect 10 Crowns

King Tongue - Attack Skin 2:
Collect 20 Crowns

King Tongue - Attack Skin 3:
Collect 30 Crowns

Ping Thongue - Attack Skin 1:
Collect 40 Crowns

Ping Thongue - Attack Skin 2:
Collect 50 Crowns

Ping Thongue - Attack Skin 3:
Collect 60 Crowns

Queen Tongue - Attack Skin 1:
Collect 100 Crowns

Queen Tongue - Attack Skin 2:
Collect 110 Crowns

Queen Tongue - Attack Skin 3:
Collect ALL 120 Crowns