Very fun concept. It is very satisfying to manually load and pump the shotgun. I know nothing about guns, so i thought it was strange that the shell was loaded when I scrolled up. But then I searched on youtube, and that is how they work indeed. Haha. I like how you can roll the wheel "1 tick", to check the chamber.
The only two issues that I found were, on the browser version, the game didn't captured my mouse at all, so aiming was not possible.
On the download version, when I press ESC to quit, it says to click to capture the mouse, but it didn't worked. Had to quit with ALT + F4.
No other issues than that.