GOD the DrillMan chapter where you have nothing but dozens of miniboss fights full of omega-tier viruses that you may not even have seen normal forms for yet is BRUTAL. I just got through a fight that had the exact same 3 top-tier viruses that can fill the screen with constant homing projectiles, 3 times in a row before the lineup changes for the final round. I played that one segment for like an hour straight before beating it and it really felt like it was chip luck more than skill that got me through it ;-;
