Destroy one enemy.
Complete first stage.
Destroy ten enemies.
Destroy one hundred enemies.
Complete second world and collect all the keys.
Complete first world and collect all the keys.
Beat first boss.
Complete third world and collect all the keys.
Beat second boss.
Complete fourth world and collect all the keys.
Complete fifth world and collect all the keys.
Complete sixth world and collect all the keys.
Beat third boss.
Complete seventh world and collect all the keys.
Complete eighth world and collect all the keys.
Complete ninth world and collect all the keys.
Beat fourth boss.
Complete tenth world and collect all the keys.