What's New

- better cope with Control Center
- bigger ogres & balls
- bug fixes

App Description

“Which number can divide this ogre’s number? Quick!!”

Welcome to “Prime Number Island”!
This is an educational game of defeating ogres by throwing Prime Number Balls that can divide the numbers on the ogre.

[ Important Notice - Control Center ]
The main operation in this app is swiping balls from the bottom of the screen. If your iOS7 device turns on “Settings” —>”Control Center”—>”Access Within Apps”, the Control Center may be unintentionally launched in the middle of the game. In those cases, we recommend turning off “Access Within Apps” before you play this app.

●Develop division calculation ability by learning the idea of prime numbers
This game will develop division calculation ability by working out which number can be divided by which number quickly.
Because the balls are only prime numbers, player will easily learn the idea of prime numbers - not only 2 or 3, but also 17 or 47 or 83.

●3 stage levels
Player can choose the stage level from: up to 30/up to 60/up to 100. Kids of lower age can easily start from Level 1.


●Collection of “kawaii” characters
The rare characters will appear if you defeat many ogres. You can see them in the Dictionary at any time once you defeat a new kind.
The higher the level goes, the more characters will show up.

iPhone Screenshots

(click to enlarge)

Ogre Busters screenshot 1 Ogre Busters screenshot 2 Ogre Busters screenshot 3 Ogre Busters screenshot 4 Ogre Busters screenshot 5

iPad Screenshots

(click to enlarge)

Ogre Busters screenshot 6 Ogre Busters screenshot 7 Ogre Busters screenshot 8 Ogre Busters screenshot 9 Ogre Busters screenshot 10

App Changes

  • August 05, 2014 Initial release

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