There's fascination and frustration with this kit.What you get is a box full of bags. About ten or so, each with totally random parts. The bags are numbered for certain stages, but I found that all the parts required for a given stage weren't in the specific bag for that stage, so I ended up opening all the bags. Any given step often requires sorting through two, three or more bags. In order to even try to complete the build you have to open all the bags eventually and search for even the most basic part. This is not fun, though I guess it might be STEM training for accountants (that would be the M, though maybe for kits like this it should be “STEAM” to account for accounting, and reflecting the exasperation you’ll feel). No slam to accountants, but if you are an accountant Lego models will drive you absolutely mad. Oh, and on the accountant side of things, this kit is a surprisingly good bargain for a Lego model. I thought I might try their Land Rover model, but it was over twice the price (possibly due to licensing fees).Despite what may seem like a negative review, I really enjoyed this build, and was fascinated by the design while building it. But I don't think LEGO is keeping up with the magnitude of their models on the production/delivery end. They keep doing amazing things in the design/engineering department (this model is a glowing example), but they just can't seem to get the parts (or “fulfillment”) right, which is strange given the manufacturing and tracking available today.There's a bit of anxiety with any Lego kit, especially as you near the end. With this kit, the anxiety is amplified by the number of parts (1132) and is warranted. there's roughly 8 parts that just aren't there (some similar parts but not the actual part). More surprising, there are 40 random pieces left over. And no, I didn't skip anything – I confirmed each step by carefully comparing everything to the instruction diagrams. But there's just a grab-bag of weird parts left over, and I had to substitute parts where possible.That seems to be a given with Lego... so much so that they offer a complete list of part numbers at the end of the manual, with a web url that I assume will ship missing parts. That's great, right? Well, maybe not so great – much of the build is sequential, so you would have to remove parts to replace the missing ones, Or you might think "we'll just wait on this until the part arrives." You and/or your child would lose interest after a few of these instances (again, I noted 8 mostly at the end, and there were likely more not less).This took me three days... about 25 hours or so (I'm retired). I am not a Lego guy (I am a Mars Rover guy), but I am a visual person with eye/hand coordination. Again, there's fascination and frustration with this kit.If you're the parent of a child doing this, then you might suggest doing it together. We old folk are used to dealing with disappointment, and then finding solutions. I think going through that mental process together may be the best gift you can give your kids, since it's real life.All in all, an amazing model that is a joy to assemble, but a bit tainted by the usual Lego parts thing. On the positive side, there are numerous surprises along the way. The suspension and steering are amazing (the steering is pretty loose due to the number of mechanical connections, mechanisms, and the nature of plastic, but it's not a huge deal). And yes, there are two steering modes as in the actual rover… one turns in a typical arc and the other allows the rover to spin on a dime as with the real rover. This is just insane for a Lego model to replicate – absolutely fantastic engineering and design!Oh, and one quick note on the decals: I would recommend applying them *while* assembling (in other words, when the directions say to do so). I was so into the building part that I thought "I'll just apply them after everything is built." This can be done, but it's more difficult to get them placed well. Two things that make this easier: some nylon tweezers to handle the decals while positioning them (typically used for model building when you don't want to scratch parts) and an X-acto knife (or some similar sharp blade) for when you need to lift the decal off if it's not quite positioned to your liking... the blade can be used to lift a corner enough to give the nylon tweezers something to grip. When (not if :) you need to lift a decal off, pull slowly and keep the tweezers in line with the decal (meaning don't bend the decal with the tweezers – lift slowly and directly up).My favorite mechanical treat was a total surprise. Early in the build, you’re doing things that aren’t really clear, but you just follow the directions. At the end of the 250-page instruction book, you’re treated to something truly cool – SPOILER ALERT AHEAD!Seriously. Don't read the rest of the review.Sigh... okay. I tried. So there are two “pipes” poking out of the back, which I thought was strange since they aren’t on the actual rover. Turns out these are knobs for lowering and rotating the proboscis (the sensor in front). The mechanisms are created early on and are hidden, but they are just an incredible example of the thought that went into this kit. They’re somewhat of an Easter egg… you only discover the function in the last few pages.Pretty freaking awesome bit of thought and engineering. I’d give this 5 stars for that feature alone, but I can’t give it that rating because they really have to get their parts thing together, especially as they develop more intricate kits. This isn’t 1980.So see this as a 4.8 star review.