Space Invaders

Add PowerUps:

   Add Shield

      Shield Spawner spawns 2 shields at random position.

      Picking up a shield always activates a fresh one.

      If a shield is already active, it gets replaced.

      The player can continuously pick up shields without restriction.

   Add FireRate boost of 75% (NOTE: Default fire rate is decreased to .75 in order         game to be more challenging)

      FireRate Spawner spawns 3 boosters at random position.

      Every pickup activates a fresh effect.

      Any existing fire rate effect is replaced cleanly.

      The player can pick up repeatedly without restriction.

Add new enemy kind Asteroid - act as a mine (2 lifes)

   Create new AsteroidSpawner

   Animate rotating the asteroid

Modify enemy type DiagonalShooter to be able to move vertically 

   Rework Enemy script to add vertical movement (for the Left and Right enemy in        Level1)

   Add Scroll Direction Vertical 

Add 2 new EnemySpawners

   EnemySpawnerDiagonalChaser

   EnemySpawnerStraightChaser

Credits:

Created by Yanislav Georgiev