Oh friend, I would like to say it would be cool to make a free mode, where money is infinite. I would love to play around with crazy combinations. I play on easy usually so I can try all types of combinations. So fun, love it. Here is a pic on one of my runs, I like the stone towers as well. I try my best to keep it symmetrical but oh well.
So glad you are enjoying yourself! I definitely plan a major update to this game in the future with more features, like and endless mode, and a free mode!
In the meantime though, if you type the phrase 'secretcode' you can unlock the dev console, which gives you access to many powers. But keep it a secret ;)