I actually made a lightgun game for ludum dare a couple years ago and I remember how surprisingly difficult it was to make one of these, so good job pulling it off. The world needs more lightgun games!
The CRT effect and UI elements looked really nice and gave the game a needed visuals boost to make up for the complete lack of lighting (which i assume is a construct issue?)
While way too short, the game does feel polished and well made. I only wish I could play more than just the first level. Good job and I hope you develop it further!