A friend of mine and I created a free tower defense game for the iPad. It is called Buggle TD Tower Defense.
You can find it here: https://itunes.apple.com/gb/app/buggle-td-tower-defense-50/id952327380
I know there are thousands already. But at the time when I started the idea inspired by the Desktop Tower Defense game that I could not find on iPad, I was missing strategic TD games.
We are currently doing public beta testing to figure out if the game is understandable and fun to play.
So if you have any (harsh, but) constructive feedback we would be happy to listen to you and incorporate your ideas. We would also be willing to answer any questions you might have regarding the game or the game development process.
We put a lot of time and effort into the game. It is so much more complicated and expensive to get a product out there than we initially thought.
Thank you for reading this!
PS.: I also asked for feedback on r/towerdefense. But so far, we did not get any comment. :(