If you've ever played "Snake," you understand the basic concept here. Use the arrow keys to guide your snake around the board, picking up gems as you go along. But be careful not to touch the walls, any obstacles, your body, or your opponent's body, or your snake will die. As a bonus, try to gobble up the red X for extra goodies (adding an obstacle to the board, shortening your snake, switching the left/right keys, etc.). If you sign up for a Spogg account, you can enable the chat function within the game, but it's not required for public game playing.