Credits in Theme Park Tycoon 2 are a rare currency used for special purchases, not the normal money you earn from guests. They are mainly spent on things like buying extra land plots and unlocking ride skins/customization , and they can also be earned through missions, achievements, or bought with Robux.

What they do

  • Buy more land/plots so you can expand your park.
  • Unlock ride skins and other special customization options.
  • In some discussions and guides, they’re also described as a premium currency for special upgrades or items.

How you get them

  • Completing missions.
  • Earning achievement rewards.
  • Purchasing them with Robux in the shop.

Simple example

If your park is getting crowded, credits can help you unlock more space instead of being stuck with the original layout. That makes them useful for expansion and for making rides look different from everyone else’s park.

TL;DR: Credits are the game’s special currency for expansion and customization, especially plots and ride skins.