CP Knowledge: System Defender

Welcome to another post of the series CP Knowledge. This is a series where I will talk about every single minigame on Club Penguin, continuing today with System Defender. The posts include how you play the game, its history, stamps, trivia, high scores, and a personal review of the game! Hope you enjoy it!


System Defender is a tower defense single-player minigame accessible through the EPF Command Room. Therefore, it can only be played by EPF agents. It is set in the EPF Mainframe computer The objective of the game is to protect the computer from threats. This is done by buying and placing down different cannons that shoot the enemy bots. To know which cannon to buy, G and other characters will tell you what’s going on. There is also a rectangle displaying which enemies are coming next. If enough bots make it into the computer processor, you will lose the level. 

   There are six different levels, seven if you include the tutorial. For some reason, they don’t have names, although they are commonly referred to as the name of the stamp you get for completing the respective level. The stamps are the following: Bug Overload, Herbert Attacks, Klutzy Attack, Test Bot Trio (often just called Test Bots), Protobot Attack, and Track Herbert. Each level has a unique track for the enemy bots to travel, and different spots to put down the cannons.


The in-game currency is energy, of which you have a starting amount of 200, and earn more for destroying the bots. Sometimes enemies also drop extra energy, ranging from 5 to 50. There are three types of cannonsred, yellow, and purple. The red cannons are the cheapest, purchasable for only 50 energy. The red cannons fire rate is very high, but they are weak in terms of damage. It also does not have a large area of effect. Yellow cannons have an extremely long range, but a moderate firing speed and damage. Yellow cannons can be bought for 125 energy. The most expensive cannon is the purple one, it costs 200 energy. It does a huge amount of damage, but shoots very slowly and misses the fast bots quite often. The range is similar to the red cannon, which is fairly small.

   Gears are items used for upgrading cannons. They are sometimes dropped by boss bots but are also available for 500 energy. You can upgrade a cannon a total of two times. When upgrading a red cannon, the number of shots per hit is increased. For yellow cannons, the range and damage increase. When gears are used on purple cannons, they both increase damage and adds mini cannons. The added shots make a fair amount of damage and are somewhat faster than the regular one.


Just like the cannons, the enemy bots also come in three types – red, yellow, and purple. It kind of goes without saying, but the red cannons work best for the red bots, yellow for yellow, and purple for purple. The red bots are moderately fast and always come in groups. Yellow bots are extremely fast, but fortunately, they don’t have much health. Purple bots are however quite the opposite, they are very slow but can take big chunks of damage. There are also boss bots, which are bigger versions of the normal bots. They are much harder to destroy and do a substantial amount of damage if they reach the processor. 


System Defender was released on January 14, 2011, and was never discontinued. On CPRewritten the game is currently in development due to the switch to HTML5. Upon release, only two levels – Bug Overload and Protobot Attack – were available, along with the tutorial. About a week and a half later, the game saw its first update, containing the level Herbert Attacks. Another week and a half went by until the next update, where the Test Bots level was introduced. Yet another week and a half later the Klutzy Attack level came into the game. And yet another week and a ha-, nah, just kidding. The next update, which consisted of the Track Herbert level, was seen in August 2011. But how did all this start? Why would anyone want to attack the EPF?


The leader of all these bots is the Ultimate Proto-Bot 10000 (UP10K or Protobot for short), he is a gigantic robot and a major antagonist in Club Penguin. He was created by the Test Bots, and who are the Test Bots? They were made by Gary the Gadget Guy, supposedly in 2008. Gary had decided to make penguin-like robots that would help him test his more dangerous inventions. But one day the Test Bots went haywire and disappeared. That caused Gary to create the Robo-Tracker 3000 to locate them again. The tracker led Gary to the mine, where he accidentally got stuck under a Mine Cart with no memory of what had happened. A few days later, he was rescued and healed from his amnesia. The Test Bots started stealing various items from around the island, causing worry among the penguins.

   However, the EPF was on it, they managed to deactivate all three Test Bots and threw a celebration party afterwards. The end? No, the reason behind the Test Bots stealing things was to build the Ultimate Proto-bot 10000. The Protobot had kidnapped Gary and all of the Elite Puffles. He almost managed to take over the island but was finally stopped by the trusty EPF.

   In System Defender, the Protobot makes his return. The EPF found out that he was rebuilt by Herbert and that they were working together. But they were not alone. “Hey everyone! I have a theory- I think Herbert and Protobot may have helpers! Something with a tire… maybe some kind of evil wheelbarrow?” is a message sent to the Spy Phone by Rookie on February 5, 2011. This is a reference to the Test BotWheel Bot’. The Test Bots were rumoured to get their own level in System Defender. This was confirmed five days later when the update containing the level Test Bots Trio was released. 

   Herbert and Protobot continued to work together, and they tried to ruin the Earth Day Party of 2012 with the Test Bots. But they were defeated by the EPF. After that, Herbert and Protobot got into a disagreement, Herbert wanted to defeat the EPF, and take over the island. Protobot wanted to permanently destroy them. That caused them to break their alliance, and Herbert gave away Protobot’s location. He was then defeated by the EPF using a water cannon. Since then, Protobot and the Test Bots has had multiple appearances with different stories, but none related to System Defender. 


There are currently thirteen available stamps. Two easy ones, six of medium difficulty, four that are considered hard, and one extreme stamp.


In System Defender, coins are earned by destroying the enemies. One coin per destroyed enemy, with no way of getting more or less. It is in no way a great game for getting coins, not even a good game in those terms. But the game has lots of other qualities to make up for that.


  • The Bug Overload was caused by Rookie when he read ‘computer bugs’ as ‘computer hugs’.
  • There used to be a ‘Ready For Duty’ stamp that was earned by completing the tutorial. It was on CPRewritten removed on January 24, 2018, due to a glitch.
  • Three stamps never made it into the game. They are known as Energy 9999, Strategic 318, and Strategic Expert.
  • There was a Card-Jitsu card named Enemy Bots, which depicted the three bots in the game. But it also featured an unseen fourth bot. It was spherical and dark black, with aqua blue coloured eyes.
  • It used to be possible to add Protobot and the Test Bots to your friend list using a web control cheat.
  • Protobot is the only invention to end with 10000, as most inventions end with either 3000 or 1000. This is probably to show his superiority.
  • Protobot’s secondary language is binary code.
  • In the Klutzy level, Klutzy mistook Herbert’s computer for an arcade and attacked the EPF.


I think that System Defender is a great game, and will actually give my first 10/10. So far, my highest wanted game is Aqua Grabber with 9/10 points, but I want to say that System Defender is slightly better. If you don’t watch any tutorials, completing all the different levels and earning all stamps is a real challenge. The levels also have fun little stories within them, so what more can you ask for? Well, maybe a pause button, but you can’t get everything. I rate this game a 10/10, and highly recommend everyone to play it once it is up and running again!

Did I miss anything? What do you think of System Defender? Comment below!

That’s all for me today, hope you enjoyed this post! See ya next time!

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