Kraid is some hot steaming bullshit, I didn't think a videogame boss could get worse than that. Until I reached Mother Brain. Ooh boy.
Homing projectiles coming at you from every angle... A tiny space to move... Your target can only be shot from a tiny hole... And if something hits you (and it will, OH IT WILL DEFINETLY WILL) you'll most likely fall into a lava pit that constantly drains your health, slows you down and sometimes will not let you get back to your tiny platform because of course: the physics on the lava are all over the place.
Yup, that's the original Mother Brain ya'll! 10/10, best boss battle of all time xD