This was painful. I see how much work went into this, and it's really unfortunate that you didn't have more time to finish things up. I'm just going to point out a few things that would have greatly improved my experience without much effort.
First up, tell people how to play the game haha. It took me a few minutes of pressing every button on my keyboard to figure out how to build turrets and start waves, and after 5-10 minutes of playing, that's all I managed to figure out.
I'm assuming there's a way to get turret ammo back, but I have no idea how to do that aside from selling and re-purchasing the turret. This made the game way too difficult. I'm assuming there's a mechanic I'm missing, but that was my experience.
Making a tower defense game in a week is really impressive, and with some more time, I'm sure you could make this really fun to play. Good luck in the future.