Space Invaders

Based on original Space Invaders arcade game.

How to Play:

1. Use the left and right arrows to move the laser cannon left and right across the screen.
   
2. Use the space button to fire the laser at the invaders. Only one laser can be fired a time.
   
3. There are 3 types of alien invaders which are worth 10, 20, and 30 points respectively. They drop missiles as they move across the screen. If a missile hits your laser cannon, you lose a life. You have 3 lives in the game.
   
4. At some point in the game, a mystery ship will appear on the screen that is worth a significant amount of points. It will only cross the screen one time.
5. The game will end if the invaders reach the level of your cannon.
   

Good luck!