Firstly: I downloaded the game, and it works fine locally. You should probably tick the checkbox that says "This file will be played in the browser", and your game will show up on the webpage, which will make it easier for people to play. 🙂
I like the concept! "Watching paint dry" was the very first thing I thought of when the theme was revealed, and I thought it would be funny, but I couldn't think of anything I could actually make for a game. This is a great interpretation of that! The rouge-like addition was clever.
I think it could be better explained that you have to click on the enemies with your mouse. I thought you just had to aim the shotgun and it would hurt all the enemies in its path. Also, I played on Easy and it sometimes feels like I can't shoot fast enough to actually kill the enemies, so there might need to be some tweaking of the gun damage, fire rate, and/or enemy health.
Good submission!
