Here is the full list of all 19 Rocket Blasters achievements.
Destroy Three Colossal Dreadnoughts
Destroy Five Pizza Armada Battleships
Destroy Three Pizza Armada Battleships
Destroy 25 Enemy Drones with Side Cannons
Destroy Five Hundred Asteroids
Destroy 25 Enemy Drones with Destructo Beam
Destroy 25 Enemy Drones with Triple Blasters
Destroy 25 Enemy Drones with Energy Shield
Reach a High Score of 1000
Destroy One Hundred Enemy Drones
Enter the Ice Caves of Yorg
Destroy One Colossal Dreadnought
Reach a High Score of 100
Reach a High Score of 500
Destroy a Pizza Armada Battleship
Destroy Fifty Enemy Drones
Destroy One Hundred Asteroids
Destroy Fifty Asteroids
Destroy Ten Enemy Drones