Torso and title make no sense

This movie is officially known as 'Monty Python and the Holy Grail', right? However, in the actual titlecard in the actual movie, it says something about 'Quest for the Holy Grail', so which is it? The title makes no sense.

When the 'black night' has his arms and legs cut off (he would've at least passed out from the loss of blood from just one arm being cut off, not to mention the disorientation brought by the pain - there's no way he could've continued a casual conversation and debate about 'flesh wounds'), his body is just a torso.

However, he moves his head rapidly, while turning his neck and shoulders - there's NO WAY a torso could do that without falling over, especially since he is wearing a heavy, metal helmet.

The way he's moving about would be impossible for a torso, he would've fallen over many times (or just once, and then not be able to get up again).

The torso movement and standing up and staying up kills the immersion, as it's not realistic at all. They should've found an actor, whose body IS an actual torso for realism. Why not? They did it for the one-legged man, so why not the rest of it?

This scene is also unrealistic due to the two-handed sword being wielded with only one hand (because the other hand and the whole arm just isn't usable anymore after it has been cut off). I mean, the loss of blood, passing out, etc. aside, you can't just wield two-handed sword with one hand for all kinds of reasons.

There's the whole 'balancing thing' that you can no longer do properly, there's the 'not-trained-for-it' - after all, you have been trained to handle it with two hands, how are you suddenly going to adjust the completely different way of using it with only one hand?

It's also too heavy for one hand, you can't move it the same way (with one hand, you can move the tip effectively, by grabbing the sword at a lower point while the other hand keeps it balanced - how do you do that with only one hand?), and furthermore, YOUR OWN balance point has now changed, you can't counterbalance with your other hand even if you DO use it with one hand - there's no way you could basically do anything useful with it in that situation.

Not to mention you'd have to re-learn balance all over again because your whole body would feel different due to missing arm, plus the armor would still create further problems with balance. Basically you'd have to learn to 'walk all over again' because the balance would be so different now. Effective dueling in that situation?! NO WAY!

ALL that aside, 'what are you gonna do, bleed on me?' is a bit unrealistic - after all, even with only one leg, he still has that heavy helmet he could've used to punch the king in the face or something. I mean, if he's so resilient he doesn't feel pain or faint from blood loss, and instantly learns how to 're-balance', he should be able to form more effective attacks.

Not to mention the fight looks nothing like the previous fight - instead, it looks like the knight is trying to let the king win, and not do anything actually effective. Also, such tiny movements and small amount of force would not be enough to cut off an armored night's arms. Why does he not wear better armor for his shoulders anyway?

Human bone + muscle + cloth + armor should not be cuttable with such flimsy 'barely motions', no matter HOW sharp your sword might be (and they don't look particularly sharp).

This whole scene makes NO sense, I don't know why they let it look like this. At least make it look like a realistic swing and don't make the knight just run straight with the sword pointing forward, it looks so stupid and unrealistic.