I know another review said this, but it feels so empty without any form of sound. I would recommend freesound.org for sound effects as sound can really improve an environment. Also the viewport gets a bit messed up due to the camera not expanding with the window so playing on a 16:9 ratio monitor looks a bit strange around the edges where it goes to grey. The theme is only really in the towers getting bigger and the gameplay gets pretty boring once you've built 5 towers and saved up to upgrade them all due to the towers being too good at defending the building too early on so there's no sense of challenge or skill but you don't get infinite floods of money either so you just sit there, waiting.