Very nice execution: aesthetics, visuals, music are on a high level. I dropped a point for visuals because UI did not look pleasing and the + - "unlock" buttons were not responsive (sometimes i could not click some op them at all or needed to point my mouse to an exact part of a button. Also some tutorial would be useful (I was mostly bothered about timing (when I needed to buy new units, when I needed to start the attack etc ), but maybe it is just me because I am not into tower defence or strategic games). But again, overall it is very well done.