My first iPhone app, StickWars, was built using cocos2d. I obviously can't say enough about how I couldn't have done it without cocos2d, and I will find ways to give back to the community behind this great work.
StickWars was one of the first castle defense games on the AppStore (XGen Studio's Defend your Castle actually beat mine by a few days, but wasn't as popular). The concept behind the game is simple--drag charging enemies in the air with your finger, and drop them on the ground. However, there are many more elements that come into play later on to keep it interesting after the first 3 minutes :).
Let me know if anyone actually wants some promo codes, I'd be glad to post them here, even though I'm slowly running out as Apple has sat on my last update for about 3 weeks now.
From a technical side, I can tell you that it is amazing that StickWars actually runs, much less is playable. I was learning everything I was going, and coming from a Java background, programming in ObjC on a small device is a very new perspective. If anybody has any questions, I love answering questions from developers, as long as I can figure out the answer.

Homepage
http://johnehartzog.com/projects/stickwars/
Full version:
http://itunes.apple.com/WebObjects/MZStore.woa/wa/viewSoftware?id=309527804&mt=8
Lite version:
http://itunes.apple.com/WebObjects/MZStore.woa/wa/viewSoftware?id=309528712&mt=8
[edited img link by admin]