Lightgun build added

Here is a quick fix that should make playing it arcade style more feasible, namely two changes: The lightgun build has increased hitbox sizes, making it far easier to hit a target. I unfortunately cannot test it myself but I think it should play way smoother now. If you want to play with a mouse, it's probably too easy now so you should play the normal version instead. The other change is that the game now runs fullscreen. If I get around to it, I will make these options toggle-able in game, for now this is a bit of a quick fix.

I hope you have fun, please let me know how it plays with a lightgun now!