The sfx from clicking on part of the background was a nice touch, giving character to the game.
The UI was identifiable in the main game scene, along with the tips for what each item does helped me understand how to use each item.
Upon the game commencing, I just fell into the groove of the game. I liked the upgrades that were possible for the towers. The types of enemies were fun and the wave information on the right of the screen was nice to see as well, from a players perspective and developers one to (it's clear a lot went into the making of this game).
I enjoyed the music for the game, felt at home with the gameplay. The art was pleasing to me and overall. Had a nice time trying your game out. Well done :). Oh, the theme for your game too, shaman etc. Love it!