Thank you for playing! I'm glad you enjoyed the gameplay and art. Yes it has come to our attention that some people have trouble with the shaders specifically the final boss one. We have some theories about it, but during the development time for the Jam, we did not catch it and we did not have enough time to have it tested. But we will see what we can do post Jam.
Glad you did not run out of fingers, some people do. So I'm glad the difficulty curve is not so out of balance, even if it does need some tweaking.