I enjoyed the game. The mechanics are easy to learn, just start playing. The boss fight surprised me.
Maybe add buildings that require more interaction than just one whack? Maybed add a building that is on fire and you need to put the fire out before fixing it?
Also good job Peter! The game soundtrack reminded me of old MSX Konami SCC cartridge music in a good way. The Konami SCC cartridge had small soundbanks with five channels in addition to the computer's three and the games sounded awesome for the time.
I was hoping more control options since im deeply left handed and wasd doesn't work for me too well. Maybe add cursor keys and other alternatives later on? The controls are a bit confusing too. I'd ditch the mouse alltogether. Since you can do all the stuff with keyboard anyway, why require mouse clicks?
All in all. Nice game with easy gameplay mechanic. You guys have a good foundation to improve on and add to.