# Mandatory Features
The user must be able to indicate he or she has acted contributingly towards her score. These actions include and are limited to:
* Eating a vegetarian meal
* Buying local produce
* Using the bike instead of the car
* Using public transport instead of the car
* Lowering the temperature of your home
* Installing solar panels

The score should be expressed in the amount of CO2 you save, and should be shared/compared with your friends. The user should also receive badges or achievements etc. for achieving certain scores. Bonus features **do** add additional points to the grade.