Well, I don't know the complete ins and outs of it, but you have to shoot him at a very particular moment and his mouth somewhat freezes in the open position. In my opinion it was never the intention of the developers as Kraid never get the opportunity to stand up and therefore the screen never scrolls over once he is defeated (you have to blindly go into the varia suit room to get the screen to scroll). This tells me that it's not really an intended strat and more so Kraid taking damage with the super missle on a certain frame is what prompts his mouth to stay open longer than intended. It's a little more complex than just blasting Kraid really fast with X number of super missles at the beginning of the fight... the timing is pretty precise. If you simply mash super missle while his mouth is open for the designed duration you will not kill him. I would definitely consider it an exploit for those reasons.

 

OK, I must have misunderstood what was happening in the video when I watched it before (without sound).

 

Yeah, it's a hard catch. Honestly I thought the exact same thing when I first learned the trick... I couldn't figure out how the guy in the video was getting so many super missles off before Kraid closed his mouth. But if you damage him just as he is opening his mouth it 'stalls' the animation and allows you to hit him with one extra missle and kill him. I am not sure why this happens though.. I assume something in the code acts up when he takes damage - I really have no clue. Not only is it a precise timing, but also a precise shot as you only have a few pixels to work with between his snout and raising claw. For me though, it's really the lack of him standing and the way the screen won't scroll that gives it away as an unintended strat. That's why I also think the mach ball was an oversight by the developers. I can't imagine them putting something that subtle in the game that allows you to skip one of the first main bosses of the game.

I agree that the KQK was an oversight by the developers. It doesn't have to be a precise shot though. If you start with a charged shot instead of missiles as an opener it'll lock Kraid's hand into whichever position it was in. I use the charge shot KQK as it's what I had learned first and it makes the kill easier. I always find the lag that room generates messes me up when using missiles in the beginning.

Exploiting every programming error makes the game that much more fun