Wow this frustating xD but then again I never understood why people loved the original so much - so I am not your audience...sorry
Your boss fight is in my opinion close to impossible with bad luck - if he comes close to you and has anything but the smallest pipes - you basically can't dodge so I gave up after a few attempts
Also I don't know if it would be better but for me shooting and clicking with the same hand was mindbending I had to concentrate just to keep holding RMB
But keep at it maybe with a few tweaks it can be fun even for people like me^^