Starting Out
Finish first two levels.

World 1
Finish first cup.

Skull Breaker
Hit yor head 50 times.

One More Time
100 Restarts.

World 2
Finish second cup.

World 3
Complete third cup.

World 4
Complete fourth cup.

Master Skeleton
Complete the game.

Smooth Rock
Complete first track in 'Rocks' cup without falling.