In The Final Earth 2, you can use so-called secret codes, which - upon their activation - will give you (for example) more cosmetic variations of buildings, show you advanced statistics of your colony, and etc.
This guide will tell you how to use them and will list all of them.

If you know where secret codes are located, skip this part. If you don't, continue.
Step 1: Click on the Game Menu button


Step 2: Click on the Advanced Setting button


Step 3: Click on Input Secret Code


Step 4: Click on Enter Secret Code and write the secret code you want to use. You don't need to press Enter or any other key to submit the code - if you wrote it correctly, it will be used automatically.


Step 5: Enjoy (I used Dance All Night code for this)!

This is the list of all (known) secret codes.

• Orchid: Unlocks new flower variants in a Park.
  
• Dance All Night: Allows you to customise lights in a Night Club
  
• Stats: Shows you stats about your city (number of buildings, how tall is highest building, how many times were landing pads used, number of citizens' names and most frequently used name
  
• Coolmath: Same as Stats.
  
• debug_pathfinder: Some pathfinder debug. To be honest, I have no clue how it works.
  
• compat no masking: I don't know how this works either. Thanks,
  Unit1208!
  
• Hangar: Allows you to customise spaceships in Landing Pad.
  
• Maximum Lag: Removes the population limit. Thanks, cappoSB!

- Doesn't matter if you write in lowercase or uppercase. orchid, ORCHID and orCHiD should work same.