Go through the list of issues on the github repo and try to fix as many as you can.
The games, number of bugs and their difficulty are listed here:
| Game | Bugs |
|---|---|
| Asteroids Infinity | 1 |
| Keyboard Interaction | 1 |
| Tetris | 3 |
| Tic Tac Toe | 3 |
| Pong | 1 |
| Shift Puzzle | 1 |
| Conway's Game of Life | 1 |
| Hangman | 1 |
| Snake Game | 2 |
| Flappy Bird | 1 |