The game consists of only one simple rule and three ways to win. Rules:

• Pieces move in a straight line, including diagonally, as far as possible with no jumps.

Ways to win:

1. Arrange your pieces in a straight line on the board (not diagonally)
2. Occupy four corners of the board
3. Form a 2x2 square anywhere on the board

Here is the source code

You can also try the in-development online multiplayer version of the game here.