Thank you very much and congratulations on completing the game, it made my day.
As for the last boss, he is indeed challenging, but he only has 3 lives to compensate (less than some common enemies in the game) and his attack is interrupted by being shot. So he is aggressive and requires a defensive approach to balance things out. Each type of block structure, lateral and vertical, allows you to avoid one of the attacks. If someone understands the puzzle of this fight, it will still be difficult, as it still requires quick reflexes to attack and evade.
Thanks for sharing your experience, I will take it into consideration when balancing the difficulty of my future games.
I am also glad that the enemies fit the theme of this GameJam, they really are nightmare fuel.