Yes, the flying enemies were definitely the Al I spent the most time working on, they gave me a lot of trouble during development. Even on the very last day I had to upload a quick fix to correct some of their behavior :) The idea of adding checkpoints has been suggested quite a bit, and I really like it too!
As for the boss, the spot where you could cheese the fight was actually intentional, it's there so that players who got stuck or frustrated could still finish the game if they wante to.
Thanks so much for playing our game! And haha, we'd love to see your brothers hitless run if you manage one ❤️