Spoilers: In level 30, you need to enter the first letter of the numbers 1-30 in order. First you click "O", because it's the first letter in "one", then you click "T", because it's the first letter in "two", then you click "T", because it's the first letter in "three", etc, all the way until you hit 30. Hopefully this helps others; I was frustrated because nobody explained it clearly.
 "Farragomate"){kind=icon}
 "What's inside the box?"){kind=icon}
 "AdVenture Capitalist"){kind=icon}
 "Learn to Fly 2"){kind=icon}
 "Learn to Fly Idle"){kind=icon}