Challenges

1. (Easy) Change the background of the game
2. (Easy) Get the hero to move up and down
3. (Easy) Get 7 enemies to show up instead of 4 at a time
4. (Intermediate) Get another type of enemy airplane to show up
5. (Advanced) Collision Detection for the airplanes – when the hero collides with the enemy, have your score go down by 500.
6. (Advanced) Collision Detection for the bullet – Have the score go up by 10 when an enemy is struck down.
7. (Advanced) Get the enemy to explode when it is hit
8. (Advanced) When the bullet hits, make a sound.