Completed the tutorial
Completed "Little Invaders" chapter
Completed "Nocturnal Experiments" chapter
Completed "Hell's Kitchen" chapter
Completed "The Disclosure" chapter
Completed "Stairway to Death" chapter
Unlocked a level with 3 stars
Purchased a weapon upgrade
Purchased a special item
Purchased a skin
Purchased 2 weapon upgrades
Purchased 2 special items
Purchased 2 skins
Defeated the Giant Flambido
Defeated the Giant Toad
Defeated the Living Oven
Rescued a classmate