Got the hang of it
Great music, great graphics.
My first game went terribly. My strategy was to build many towers and upgrade them. Then I realized that the price of an upgrade seemed high and the gems as well. I also did not notice that I was acquiring accessories!
My second game, I decided to focus on fewer towers and all upgrade and it went very smoothly. I enjoyed adding different gems for a variety of combinations and attacks.
This is a great game, I'll definitely keep playing as time allows.