Hey!
I liked the theme you had going a lot! I thought the different ammo types you could switch between added a lot of cool flare and style to your game.
I got stuck at the main menu - I eventually figured out you had to click the title of the game but this wasn't really too clear. I would suggest making this a really obvious "Play" button next time. Also, I wish that the cannon could be charged + uncharged a bit faster, it was a bit tedious to have to wait a few seconds to launch a full charge shot.
I think you did a great job and am super impressed this all got made in a week. Great job :)