Gold Digger

Gold Digger is a simple alternative to minesweeper, where the goal is to make as much money as possible before you inevitably go bankrupt.

The rules are simple:

1. Pick a square to start digging. 
2. You can only dig up a square that is next to an already dug-up square.
3. It costs money to dig up a square. Each gold nugget that you find will give you extra cash.
4. When you run out of money, you lose!
5. Gold gets harder to find after completing each level. How far can you take your fortune?