Could you give an example of a sandbox game?
If it's a 2D game it should be possible.
The answer to how is pretty simple:
- Learn to understand how C2 works.
- Create your game.
This forum is full of answers and examples which may not be 100% like what you are trying to do, but when you know the basics a lot can be derived from them and sometimes you only have to change a small amount of code to get to that 100%