Man, The Yolk-Star is the hardest of the bosses I faced so far. I do play on seasoned skill level, so yeah, not that high difficulty, but even on these easier difficulties Yolk-Star is pain in the ass. On hardest difficulties it might be topped by UCO or other fast Chicken bosses, but on medium difficulty it rules and is super annoying with chickens spawning from all corners, flying at you while you try to dodge laser beams. God dammit there is probably zero try on it where I would not die or not have to use phase-out to avoid the chickens.
Yolk-Star in my opinion should either be kept for Elite missions exclusively the way it is now, or be a little bit tweaked to be more forgiving in medium missions. And from threads I am seeing now next to this post I’m typing in there are more people like me who have issues with the big ol’ Yolkie. Gotta say, it is still considerably the hardest final boss from the franchise, if we don’t count over-the-top Boss Chicken from CI1 late waves