Developers trying to cash in on popular titles are not new to the Apple App Store, notably after the success of Angry Birds spawned apps that were very similar in design with a different set of characters. However, not everybody is lucky. An app, based on tower defense title Plants vs Zombies, has been pulled.

The game was called Defend the Diayou Islands, which emerged on the Chinese App Store. As has been said before, Apple apparently gave no notice or reason for the removal according to developers Shenzhen ZQGame Network. It is apparently in discussions to relaunch the game on the App Store.

Games "cannot target a specific race, culture, real government or corporation or any other real entity" according to iOS App Store guidelines. Instead of defending a house and plant pots in Plants vs Zombies, Islands requires players to attack invaders in the form of sumo wrestlers and ninjas while defending the islands.

The Seattle Times reported that the islands, if controlled, allow access to gas and oil reserves in the real world. In an interview at All Things Digital D8, former Apple CEO Steve Jobs said there are only three reasons apps are declined: the app doesn't function as advertised, it uses private APIs or it crashes.

It's a difficult position for Apple, because are all apps similar in design to Plants vs Zombies going to be under scrutiny? Some developers are inevitably going to try and exploit the success of other apps, even if it's a rip-off. Some critics of Gameloft criticized the studio for building games similar to existing IPs, resembling some in setting: N.O.V.A. is the studio's equivalent of Halo - it even features a space marine protagonist - and Modern Combat is equivalent to Call of Duty: Modern Warfare. Gameloft has been successful, though, even if the practice is questionable.

Plants vs Zombies requires players to grow plants, defend a house and attack zombies. The game has been a critical and commercial hit for PopCap, the developers, and also launched on Xbox Live Arcade after being exclusive to iOS.

Apple hasn't commented on the news. Plants vs Zombies is available now to download for $2.99 on iPhone/iPod Touch and and $6.99 on iPad. It's also available on Android via Google Play.