Alpha Version 5

Main changes:

• Added a new enemy that fires homing missiles!
  
• Added a miniboss about halfway through the game.
  
• Destroyed enemies now have a chance of dropping Ethereum; a valuable substance that is worth Credits.
  
• The radar now warns about incoming asteroids.
• Upgraded the armament of the final boss.
  
• Increased the quantity of purchasable items in the store.
  
• Reduced the health of the big enemy so that they can be cleared out of the way using weapons.