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26 October 2026

Review: part 8057 and set 77120 Shadow's Mech vs. G.U.N. Trooper from LEGO® Sonic the Hedgehog™

Posted by Tom Loftus

Something is afoot with LEGO® Sonic the Hedgehog™ 77120 Shadow's Mech vs. G.U.N. Trooper. Today I take a look at the new 2 x 4 plate with ball joint, before analysing the other parts and the construction of the set that introduced it.


We were given this product by The LEGO Group; the author's opinions are their own.
This article contains affiliate links to LEGO.com; we may get a small commission if you purchase.

77120 Shadow's Mech vs. G.U.N. Trooper

  • Release date: 1 August 2026
  • Pieces: 374
  • Ages: 8+

Price: 

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Lego Sonic the Hedgehog 77120 Shadow’s Mech vs. G.U.N. Trooper

 

New mould: 2 x 4 Plate with Ball Joint (part 8057)

So far only found in this set, Plate Special 2 x 4 with Ball Joint in White (6591754 | 8057) feels like the kind of element that could go unnoticed – so naturally, it's essential we analyse this little beauty, not least because it was co-designed by one of our New E alumni: Aron Gerencsér! 



It's a welcome alternative joint to 2 x 2 Technic Brick with Ball and Axle Hole (57909) which can be cumbersome in some situations. The underside of the new piece (above right) strongly resembles that of a regular 2 x 4 plate, but features some extra ribbing and a teeny-tiny, plus-shaped hole in the central underside tube.



A natural companion is the 2 x 2 Technic Brick with Ball Socket (67696), though any element with a compatible socket (i.e. 10.2mm) will work. 

The height of the ball allows for ample range of motion – though the spacing is far from arbitrary: 


While it's largely pointless to do so, the joint can be fixed in place thanks to the LEGO® System-friendly geometry of the new mould.



The same spacing can't be achieved with existing parts, though a couple of studs and a Technic 10.2mm ball piece (32474) comes close.



I'm sure there's a super-collector out there that could amass every element with a 10.2mm ball for a comprehensive family photo, but hopefully the above assortment conveys the idea. It's just the latest addition to a long line of parts introduced in past CCBS themes like Slizers/Throwbots, LEGO® BIONICLE®,  LEGO® Hero Factory, LEGO® Ben 10 and many more.



Here are some other distant, LEGO System-based 'relatives'. Above left is Brick Special 2 x 4, with 2 x 2 Brick with Top Pin and 1 x 2 Side Plates (30592), often used as the mount point for rotor blades on helicopters. It's a passing resemblance at best, but I think there's some tangible kinship there. 

Same goes for the comparison above right with two 1 x 4 Plates with 2 Studs (41740) which matches the stud layout on the new joint.


A peek at the finished mech's foot demonstrates the prime reason the new joint was introduced. Its slim, plate-based design streamlines the assembly massively and allows for a sturdy, low-profile ankle joint with space around it, without relying too heavily on SNOT construction. 

However, it'll surely have utility beyond mech building too:

One possible use is as anchor points for positioning something big and heavy at a dynamic angle (I'm picturing an old-timey galleon on stormy seas, but feel free to imagine something else big and heavy at a dynamic angle). Granted, for big models, the older joint types probably could be employed just as easily, but the new plate-based element is still easier to integrate onto a studs-up surface.

The highlight parts-wise is definitely the ball joint, the the set also has selection of other goodies.


Recoloured elements

  • 1x Brick Wedged, Sloped 45° 6 x 8 with Pointed Cutout in Black (6591605 | 22390)
  • 2x Grille Bar 1 x 4 x 1 2/3 Bull Bar, Squared in White (6621051 | 77083)
  • 1x Brick Wedged, Curved Triple 4 x 4 x 2/3 with 2 Studs in Dark Green (6617307 | 45677)
  • 2x Bar 1L with Rounded End in Pearl Gold (6668515 | 7768) - Previously appeared in this colour with printing in 31386 Wild Animals: Majestic Lion

Rare parts

The following appear in 2 other sets or less:

  • 6x Brick Sloped 33° 2 x 2 Double in Dark Green (6617306 | 3300) Found in 1x other set
  • 2x Brick Special 2 x 5 with Slope, Studs on Side in Dark Green (6540945 | 79897) Found in 1x other set
  • 2x Ghost Effect with Bar in Trans-Black (6586826 | 5500) Found in 1x other set
  • 6x Technic Brick Special 1 x 2 with Ball Socket Wide in Red (6553183 | 7510) Found in 1x other set
  • 2x Vehicle Track, Roller Coaster Straight 4L in Black (6475095 | 80562) Found in 2x other sets

Minifigure

Shadow receives a new decoration on his head (6614102) and legs (6626352). The torso (6474420) is recycled from previous versions and can be found in two other sets. He also has a bike, or "Dark Rider" as it's known in-game. 


The builds 

G.U.N. Trooper

The name feels a bit contradictory to LEGO® values. Presumably the fact it's the name of an in-game entity and an acronym (Guardian Units of Nations) makes having the word gun on the box permissible? 

In any case, the side build itself is neat.

Its small size packs a great number of articulation points, including the waist, which makes the little dude highly poseable. 

As I was unaware G.U.N. troopers have absurdly wide shoulders, I initially had the upper arms connected the wrong way round (above, bottom right). I corrected my mistake for the review, but I think I prefer the erroneous configuration, it feels more natural even though it's inaccurate. 


Shadow's Mech

Unless the G.U.N. trooper bought friends, this probably won't be a fair fight...

Shadow's Mech is a solid, mid-sized mech with a build complexity befitting the target age range of 8+. There's not much in the way of fancy techniques or elaborate shaping, but the build is not without merit. 

A highlight are the sword sheaths on the thighs, which use black 4L roller coaster tracks (80562, above top left). It's an awesome use of parts and provides simple yet effective storage for the massive blades. Note the colour-blocking nearby on the shins too; extending the 45° angle of the armour piece (79897) with a pentagonal tile (22385, 35341) looks great.

The fixed knees are a bit restrictive for striking action poses, but they do make getting the model to stand much easier for younger builders. Unfortunately though, all the ball joints on my copy feel a tad loose – not much, but enough to make it tricky to pose the legs on a slidey surface or keep an arm outstretched. Hopefully I just got unlucky and it's not a widespread problem, but if it is, let's hope it's resolved swiftly.


Verdict

The price of US$49.99/ £44.99/ 49.99€/ AU$79.99 feels pretty steep for a set this size, so definitely try to find a discount if you can. Overall though, 77120 Shadow's Mech vs. G.U.N. Trooper is a fine introduction for the new ball joint mould. The two mechs are well designed and each have a selection of parts to please the MOC builders. 

READ MORE: Coming Wednesday 28 October: GwP 40889 Build, Paint and Play

 

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15 comments:

  1. Andrew Barnick26 Oct 2026, 16:59:00

    Nice review!

    I could actually see the spacing of the new joint allowing you to fix it in place horizontally being quite useful for transforming MOCs if it separates without too much trouble—for those sorts of MOCs, it can be useful to have joints that can either be articulated (for a mech/creature mode) or fixed in position (for a more rigid vehicle mode). The clean spacing could also be useful in combination with tiles if you wanted to use the joint for a high friction two-dimensional pivot instead of a joint with three dimensions of articulation (similarly to how the 2024 City Excavator and Crane sets used similar joints).

    ReplyDelete
  2. Anonymous26 Oct 2026, 23:36:00

    Any functional reason for the stems of Lego ball joints to be cross shaped, rather than circular?

    I wondered if it was to save plastic, but you could have a larger hole if circular

    ReplyDelete
    Replies
    1. Anonymous27 Oct 2026, 02:52:00

      LEGO PART 32172 Technic Pin Connector Block 3 x 3 x 1, as seen in Throwbots/Slizers.

      https://rebrickable.com/parts/32172/technic-pin-connector-block-3-x-3-x-1/

      It prevents a limb from being rotated when in an extreme position. Everything since is probably just inertia.

      Delete
    2. Bfa27 Oct 2026, 03:24:00

      I think the original purpose was to lock the Throwbot/Slizer arms in place in the 32172 connector piece used as their shoulders, so the throwing action would be easier to use. Presumably the other ball joint pieces were designed to accommodate the same piece for compatibility's sake (which continued with the new BIONICLE pieces of early 2002) and then at that point it just sort of became part of the general design language, even as the axles' design became essentially non-functional.

      There are a few pieces like the inner Rahkshi back piece, the 2014 Smaug wings, and the 2015 BIONICLE skeletal limb piece that skip the axle for aesthetic or functional reasons, and a couple of later-year pieces that are "accidentally" compatible with the connector block.

      (Are there any part databases that categorize or tag pieces by their connection points? That'd be cool to dig through.)

      Delete
    3. Skye Barnick27 Oct 2026, 04:00:00

      Another factor is that a cylinder of the same overall size as the current cross shape connection would need to be hollowed out in the center (like a Technic pin) to cool properly after molding.

      Delete
    4. Anonymous27 Oct 2026, 08:55:00

      Are there any part databases that categorize or tag pieces by their connection points?

      I reckon you could just search for the name of the connector on bricklink / stud.io

      Delete
    5. Bfa27 Oct 2026, 14:03:00

      That's what I tried with the rabbit hole that comment sent me down, but unfortunately things aren't named consistently enough for that to work. Most of the pieces with this ball (or socket) connector contain "ball joint" in the name, but some (like "Bionicle Toa Leg") don't. I also don't think including every connection point in the name is a good idea overall, given how long some pieces' names would then have to be lmao.

      I think it'd have to be some kind of new tagging system so that other info fields aren't overwhelmed, and so pieces can be filtered by the connection tags. Could also include things like equivalent gear tooth count, since we're talking about the Slizer/Roborider/BIONICLE era and many of those pieces had integrated gears in many of their pieces. This idea is really growing on me, someone should do it. I volunteer to help tag some of the pieces.

      Delete
    6. Anonymous27 Oct 2026, 22:05:00

      Apologies for sending you down this rabbit hole. I found what you dug out really interesting. An inconspicuous detail is more than an engineering feature, it’s originally part of a play feature.

      Delete
    7. havron3 Nov 2026, 18:57:00

      Try the Lego Parts Guide at Brick Architect. I have found it to be an incredibly useful resource, which categorizes parts first by broad group and then by subgroups like this. For example, under "Articulation" there are all sorts of parts categorized by connection type, including ball-and-socket.

      Delete
  3. Anonymous28 Oct 2026, 12:46:00

    Are the prices auto-generated? I see it's up for 69.99 CAD on the Canadian site.

    ReplyDelete
  4. Jimmy28 Oct 2026, 18:43:00

    Will we be getting an analysis of the part 2x Bar 1L with Rounded End in Pearl Gold (6668515 | 7768) ? I'm very curious how it is use, and what prompted it's introduction. What geometry or build feature required this part that could not be achieved with some other method?

    Whatever the reason, it'll be nice for greebling and some details I'm sure.

    ReplyDelete
    Replies
    1. Anonymous28 Oct 2026, 22:00:00

      It barely looks like Lego, so it would be interesting to hear answers to your questions.

      It reminds me more of the pins used in 1970s board games like Battleships or Mastermind.

      Delete
    2. Andrew Barnick29 Oct 2026, 16:25:00

      It has so far been used heavily as eyes, including three variants with prints (two in Creator 3-in-1 and one in the Yoda bust). For that application it reminds me most of the Bionicle "Barraki eye" piece (58176), but the flatter end and printable domed surface (unlike the Barraki eye which has an injection point on the end of the dome and thus can only be printed on the sides) make it somewhat more versatile for that sort of application.

      This set is one of the first so far to use it decoratively for a purpose other than eyes (rounding off the ends of the Technic connector hilts for the swords). I could see it being useful for applications such as that (rounding off a Technic axle hole or possibly the underside of a part with a hollow stud), as well as potentially being useful as a small connector (with its full 1L bar extension potentially being useful for securing parts like half-width Technic liftarms together).

      Delete
    3. Jimmy30 Oct 2026, 03:20:00

      Thanks for the insights Andrew. It's print-ability is a nice benefit, and I'm sure designers like having something smaller diameter than a 1x1 round tile to work with. I bet we'll see it used as a way to locate or limit the position of parts in complex off-grid assemblies.

      Delete