Thank you very much for your comment. I'm glad you enjoyed the game and came back to it :D
It's true that the bosses can be difficult. It wasn't easy to find the right balance between a game that's demanding and challenging, that's interesting enough to make you want to start again after dying many times, but that's not unfair or unnecessarily/artificially difficult.
As for the random order, let's just say it's also a way of sticking to the theme. If you ever want to practice against certain bosses, in the game settings, you can force the order of the bosses with the “speedrun” mode. Maybe this will work for you.
Anyway, thanks again for your comment :D