Agree with the other posts, love the cocos2d platform, good work and many thanks!
Game Play
Defender was a great arcade classic and I had to have it on the iPhone! Planet Defence is a horizontal scrolling space shoot-em up based on Defender.
The idea is to save the humans that roam the planet from being kidnapped by aliens that use the humans to mutate into a more dangerous form of alien.
There are different types of enemy to destroy, each with their own unique pattern of movement and attack.
Be careful to keep some humans alive, if all humans have been kidnapped the planet explodes and all aliens mutate making for a very tough challenge!
Updates
The recent update to the game makes use of the cocoslive online scoring - very neat API, they have been added to the game website http://www.faulconbridgesoftware.com.au/#highscores
There is also the much requested retro style graphics to give it that true arcade feel 
Future Updates
There have been requests for adjustments to the control mechanisms so I am working on an update that will give you control over sensitivity and 'dead zone'.
Not sure everyone agrees with my spelling of 'defence' but that's the British spelling, forgive me!
iTunes Links
Hope you enjoy the game, there is a free lite version that gives you access to the first two levels: Free - Planet Defence Lite - iTunes link
and a paid version without the restriction: Full app - Planet Defence - iTunes link
Screenshots
Have fun!