Quite a nice game overall. I liked the way the UI borders uses tiles from the art-pack, and the core idea about towers with extra buffs (weapons) to modify those in any way one wants.
Has quite confusing UI - the space to deselect; LMB/RMB on pause button to switch autostart of the next level on and off; some other things about tower management could be improved - f.e. add shift key functionality to add multiples of the same type of towers/weapons.