This is a really fun idea, and I liked the music and sound effect on the gun a lot!
One of my objectives was to steal a painting, but I couldn't figure out how to shrink one. It always said that it was too big, but I also couldn't get it to shrink with my gun.
I also didn't realize until reading the page that you used the scroll wheel to change your guns size, I would definitely teach that in game somewhere.
Awesome job!