Resouerce Chest is an additional reward that you will get for completing levels. When you complete a level, all remaining time and leftover resources fill up the chest bar.
- 2 Resources of any type count as 1 point;
- 7 seconds of the remaining time count as 1 point.
When the bar is full, you'll get a reward! The rewards may include
Coins, 
Lives, 
Boosters and 
Infinite Lives.