Assembly requires a total of 5 different hex driver sizes.
They're all included with the kit, of course. For a high-end kit like this, leaving out the tools would be a bit... ;

The main ball joints have metal screws inserted inside to maintain rigidity.
Most of the screws in this kit are made up of nut and bolt combinations like shown above.
You rarely ever tighten them with a driver. (Except for the shield.)
The user adjusts the tightness of these nut/bolt pairs to dial in the right joint strength,
and since this is a massive injection kit standing 75cm tall, this seems to be the only way to handle the weight.

Some of the pre-assembled joint parts also have metal screws inside to keep the ball joints from breaking.

Assembling the sole of the foot.

The ankle ball joints are made of heavy, solid die-cast.
This kit has to be built in order — feet, legs, torso, arms, then head.

Assembling the ankle section like so...

Even after attaching the joint cover parts, there are holes on the outside so you can use a hex driver to
adjust the joint strength.

The knee structure. It's a double ball joint.

The knees take a lot of stress, so the fixed sections are secured with metal plates too.

Even after putting the knee covers on, you can still adjust the knee joint strength through the holes.

Just one foot weighs 1.5kg. That's the weight of two PG Zetas.

Assembling the crotch section. This area takes a lot of weight too, so there's clearly been a lot of thought put into it.
It's secured with a total of 8 screws.

The leg connection ball joints that take a lot of stress are also made of metal.

Connecting the legs to the lower body.

Assembling the waist ball joint... that area is so tight that it's a bit tricky to get the nut in place. (Should've trimmed my nails before taking this photo OTL)

Securing the skirt. You have to fit the middle connector parts in one by one.

Lower waist + legs complete! If you compare the size to the "Murphy-brand nippers" (can't even remember the actual product name anymore...) sitting below, you can see just how absurdly large this thing is ^^;

The holes in the waist parts where the screws go... had way too much injection flash inside, so the screws wouldn't go in.
Cleaning them up with a hobby knife.

The upper body interior and shoulder ball joint section.

Assembling the upper body. The parts are really stripped down to just what's needed.
The cockpit doesn't even open, sheesh;

Torso complete!

The arm joint interior. Since the ball joint section is long and thin, metal rods are inserted inside like that to maintain rigidity.

Fingers literally the size of a real person's fingers. Naturally, given the scale, every single joint is articulated.

The nuts used for the finger articulation have rubber inside them. They're the same type used in the HY2M Glorious series — special nuts that are neither too stiff nor too loose, just right for smooth movement.

A strange part you don't see in other Gunpla. Looks like a piece of gum, right? It's actually rubber.

It's a nice springy rubber part. So, what exactly is this thing...

It's an elastic part that supports the finger ball joints.

Just like this. It presses down on the finger ball joints and provides just the right amount of friction
so that even hands this large — the size of a real human hand — don't feel loose.
And the result is a big success. They move with just the right feel, neither loose nor stiff.
The thumb is a bit looser than the rest though, probably because the rubber there is smaller and doesn't get as much tension...

The arm's inner frame. Every single joint on this kit is a ball joint.

Even after putting the elbow covers on, you can still adjust the joint strength through separate holes.

Assembling the shoulder joints. You can't build the arms separately and attach them —
you have to build it up piece by piece, almost like a construction job.

Assembling the armor that wraps around the shoulder joint.
You have to delicately balance a nut in that tight space and spin the bolt while holding everything in mid-air,
so it's a bit of an acrobatic task;

Now the eyes. A black sticker is applied to a semi-transparent part so that only the eyes light up.

For the LED eye lighting, the same unit from the existing HY2M MG head set is used as-is.

Dropping the MG light-up head core into that huge head makes it look really tiny...;;

The head also can't be assembled separately — you have to attach it to the body and build it up as you go.

Straight build of the main body complete!
Building non-stop, it took about 8 hours...