Fighting Site

1. Infinite enemies are added by a spawner. The generated enemies can both chase the player and shoot. Four shooters are added for each shooting enemy. 

2. Gravity is added to the player. When the user does nothing, it will fall to the ground. 

3. In Level 1, the enemy only shows itself when it's close enough to the player. Before that, it is invisible to the user. In Level 2, four-gun shooters are added. Level 3 is infinite. The player should try to stand longer and get the highest score. 

4. Rigidbody and colliders are added to the blocks. Now, the background blocks can be used for hiding, clocking bullets from the enemies, and even trap the enemies to hit and die. 

5. All the background, player image, and enemies are re-designed.