Thanks for the feedback! The jam build of the game actually included the option to disable the screen flash effect. However, based on people’s reactions, the post-jam release will see the screen flash effect reduced in intensity and be disabled by default!
Also:
Reimu just got a brand new gun and will shoot on sight, on site. The first person she sees is Sakuya
-The overview on the game page
:^) Hope this helps :^)