Definitely got a spook out of me at least once. I had an issue with the mouse not locking into the game properly which made aiming and looking around hard. Maybe enable full screen mode option on itch.io could help?
I'm glad you got spooked! I originally uploaded this game with full mode screen as an option, but the native screen resolution didn't support it, and I had to scale down. Not sure how to fix this but would be happy to implement something if possible.
