Love this game! It gave me nostalgia of the days when I played starcraft I and II. Defending and building, keeping everything balanced, it all feels great! The way new towers, buildings and options are unlocked by playing really feels rewarding too. The only thing I'd say is a shame is the difficulty curve; maybe I need to get gud :P but around the levels when you unlock the missile launcher and the fertilizer I was just stuck.
Maybe adding different difficulty options?
All in all, phenomenal job! Thanks for the nostalgia :)