September 21, 2005 (Beta Testing) October 24, 2005 (everyone)
Astro Barrier was a Club Penguin mini-game that is located in the Arcade, next to Thin Ice, and is styled around a classic arcade game. All levels were originally playable by all players. However, on July 26, 2010, non-members were only able to play until level 5.
The game is played on the green screen of the Astro Barrier arcade machine. Only the keyboard is used to play, so the buttons featured on the machine are entirely cosmetic.
The game features a space ship on the bottom of the screen and a series of targets that move back and forth along rails. Each level has its own target layout, and a number of available shots, ranging from 3 to 10. Upon shooting all targets, the player moves to the next level. Consuming all shots without hitting all targets would cost the player a life, and the player would have to restart the level.
When a target is shot, it turns red and stops moving, unless there are multiple targets on the same line in which case, it turns orange and all the targets on the same line stop moving. It will be noted that some targets can only be aimed at through narrow gaps, making hitting them impossible if a target in front of them has been shot beforehand, which requires restarting the level in this case. In addition, the shots do not instantly hit the targets and take a brief moment to travel to hit, thereby requiring careful aiming and timing.
The game ends after successfully completing all 40 levels, or earlier if the player lost all lives.
There are several types of targets introduced throughout the game, with new ones having new properties and rewarding the player with a different amount of points:
Image when hit
Appears from level
The basic targets in the game. Move at a constant speed and, when hit, stop and turn red
Small green circles
A small variant of the green targets
A wider variant of the green targets
Stunted small green circles
Stunts all targets of its kind when hit
8 of the Expert Levels
Rewards an extra life if hit before other targets
Small blue circles
A small variant of the blue targets
A wider variant of the blue targets
Makes all orange barriers in the level disappear when hit
Has to be hit twice. Turns into a regular, green target on the first hit
Small yellow circles
A small variant of the yellow targets
A wider variant of the yellow targets
Expanding green targets
Targets that expand horizontally upon being hit
An extra cannon that shoots when the player shoots. (Its shots do not affect the number of shots left.) If aimed at the player's ship, can potentially destroy it
Rewards the player with 500 points upon hitting. Only available at the end of the secret levels
Pressing left/right moves the ship in the respective direction.
Pressing the space bar makes the ship shoot.
It is possible to skip levels right after clicking start. On your keyboard press 1 to go to level 10, 2 to go to level 20, or 3 to go to level 30.
The secret levels in Astro Barrier are accessible before level 11 starts. Wait 30 seconds when the screen is showing information about the orange switch, and shoot the blue ship that appears. Then after the 10 Secret Levels, you will skip levels 10 to level 16.
The Expert Levels are accessible before level 31. Just like the first secret levels wait 25 seconds and shoot to make the turret shoot the blue ship. Then after the 10 Expert Secret Levels, you can shoot five targets with a number of 500. That means you got 2500 extra points. Then the game is won.
You can earn more points in addition to your coins by shooting at targets and blasters when they are in the Instruction Pages.
Before proceeding on to another level, a loading box will appear for about 4 seconds. This box isn't a real loading box. But if you press enter, it will disappear and you will progress to the next level.
Astro Barrier was designed to be a very early arcade game, which is why it relies solely on sound effects and has no backing track.