Well I finally managed to get the darn Android Studio to compile the debug version of Tower, but man that thing is a mother to troubleshoot.
Now my debug-Tower is laggy as heck but at least I get to see it on my Samsung Galaxy J6+ which should run it like a breeze but for some reason is slow as a Max Payne bullet time
You can get Google maps to work without a credit card. Have a look here on how to do it:
The tricky part is getting your API key generated and pasted into the Tower files. The above site has actually all the necessary steps. I've used a restricted key for Maps APIs and it works just fine