Well, thanks to my office-mate Tim, I have an old nearly-useless iphone 3g that I decided to see if I could get Robo-Ninja running on. LibGDX can build to iOS using RoboVM, so as much as I doubted it would work, it sounded fun to try. (RoboVM is a tool for compiling java code down to iOS native code, the similarity in naming is purely coincidental)
Step 1, since I'm not interested in paying Apple a $100 yearly subscription to run my code, was to jailbreak the phone. That was painful enough, searching for information and jailbreak files for a phone that old. Piles of broken links and outdated information.
Then I had to borrow a Mac laptop, since it will only build on a Mac. I installed RoboVM and all the necessary tools, and relatively quickly got Robo-Ninja running in the iOS simulator. It was a little slow, but it was Robo-Ninja!
The next hurdle was figuring out to build the ipa file (the iOS app package file, equivalent to the apk files in Android) without actually signing it with a developer certificate. At first, it kept breaking because I didn't have an apple developer account. It took about an hour of googling, but there's a newly-added flag in RoboVM that lets you skip signing. So I finally got the ipa built.
Then a good 30 more minutes futzing with the ancient jailbroken phone to figure out how to manually install an unsigned ipa file, only to find out what I suspected: I needed at least iOS 5, and this thing is stuck at 4.
Ah well, it was worth a try. Supposedly there's a few hacks that can allow an iPhone 3g to upgrade to iOS 5, so I may try one of those for fun. Until then, if anyone has a jailbroken iphone on iOS 5 or greater, and is interested in helping me see if Robo-Ninja will run on there, let me know.
Until then, I'll keep chugging away at the game. I'm working on the factory/industry area now, trying to get the tilesets and background put together. I realized today, looking at my rough pencil sketch of the world map, that I'm about 1/3 done with the level design. And probably at least 75% done with the codebase. So I'm getting there!