Crawl onto a mine without any extra lives
Complete a puzzle with a 3-star ranking
Pick up 3 extra lives
Complete all stages with a 3-star ranking
Complete a puzzle in the sand with a 3-star ranking
Wear the top hat
Push a boulder 10 times
Complete "The End?" stage with a 3-star ranking
Wear the santa hat
Step through 10 wormholes
Eat 10 bombs
Wear the explorer hat
Complete a puzzle in the snow with a 3-star ranking
Wear the golden top hat
Complete all the stages
Become looooong (76 joints or more)
Wear the fedora
Complete "Trick or Treat" stage with a 3-star ranking