Unless I'm missing out on an ultra-high resolution version hidden away somewhere, I wouldn't go so far as to say "mindblowing design and detail". Sounds like someone was too lazy to assess it further.
It's a digital painting and appears to use traditional digital painting techniques. Now, digital ~painting~ as everyone knows starts off as huge ass blocks of colour and the artist 'molds' these colours by adding more colour and streamlining the shapes and lines. Up close, digital paintings are usually not as detailed as they look scaled down, because the artists realise that when scaled down, most of that detail is lost. Hence my comment -- unless there's a higher res picture somewhere, it's hard to get the detail.
From the looks of it, it's about as detailed as any digital painting can get at this scale.
On the contrary, it's not the exceeding detail that makes this composition but rather the MINIMAL detail put into it to achieve an effect that most people here are going "OMGaWSH" at. Take for example the mobile lift there. There are a couple few strokes from the looks of it, but the effect is that it is well-defined and detailed. Try looking at that up close (if you can find the original) and going "OH. ... ... ... ... wow."
It's what you DON'T see that will really surprise you with this painting.