Don't know if there're some games of this type on IOS
Of course there are. When u use assets that are for sell you should take in acount that u may find few version of it in the market.
Until now i found only 1 that uses the same assets on ios but its not free and also was uploaded long time ago.
I also think it is a copy of the original game source that is also for sell (on unity) so no unique levels and gameplay.
But anyway this project just started as a learning project (iSpritekit and b4i) and turned out to a finish product
I will try to make more unique games for ios.
I think ios games make more revenue then android games so will try my luck on ios.