always appreciate your feedback! thanks for taking the time to check it out, and I'm glad you enjoyed :)
ah, interesting bug.
when you say 'not the bat boss, but the 1st stage bat', do you mean the first stage of the boss fight? as soon as you start the fight? I'll have to find a linux machine to test on and work out what is happening. does the game close, or freeze? did you have to fully restart the game?