Some small improvements to the game have been done:

• Increased the frequency and the speed of Bosses attacks.
• Created a how to play screen accessible from the main menu.
• Some changes on how power ups are spawned, trying to balance more the game and making it more interesting.
• Also made the boss to wait for attack when the player has not shoot the ball.

Some more updates are next to come, when the gameplay is more tested and polished.