Aw man, this is actually a great game. Both visually and how it played. I had a blast! Great job! :) Not too easy either. I like what you did in terms of AI. For two days, this is amazing! Well done! All I can really nitpick about it, is that the checkmark and cross when placing a tower aren't too visible. Might want to give them a slight background or something, and/or put them under the tower you are placing, so they appear where the player is looking. Missed them the first time around! However, that's really a minor thing!
Edit: Also, maybe up the contrast a little between the text and background of your itch.io page? It's kind of hard to read :)