No worries about rating, I always rate everyone's game whoever comments.
And yeah glad you think the boss was fair, and there's only like 2 times the boss becomes invulnerable (unless there was some glitch) when it jumps at the player and does the shield thing, but I also designed the game so that you could get overpowered with the upgrades if you figure out the right ones to pick so it makes the boss easier, but thanks for playing, i'll get to yours soon :)