You receive gems for completing levels.

After completing a level, you will have the possibility to add some Extra Gems and progress further. In most cases, you can add 20% extra and this is based on your Gems that your earned in the level.

You have 3 options
  1. Get the Extra Gems for watching an ad
  2. Get the Extra Gems by using your diamonds
  3. Close the Extra Gems Dialog and do not add any Extra Gems
Earn Extra Gems
💡 Tip: The more Gems you've earned in a level - the more Gems you can get through the ad or using your diamonds.

💡 Another Tip: Take a look in front of the Train. If you are close to a Chest of your next destination, you could use the Extra Gems to get their immediately.