Get 150 points with any character to unlock their silver skin.
Get 300 points with any character to unlock their golden skin.
Buy 3 diferent characters.
Collect 400 emerald gems.
Collect 150 diamond gems.
Buy every single character.
Get 9 gems in 3 turns.
Play 10 games
Get 10 gems in 5 turns.
Play 20 games.
Play 50 games.
Slide 30 times on ice.