4) details galore. I leave this for the next person, maybe we can spot some standard design elements.
An ass load of divets, rivets, blocky armor, holes, protrusions, and various other elements. The idea is futuristic but bulky. A good example of this is Games Workshop's Warhammer 40,000 range of miniatures.
Take a look at this tank:
http://us.games-workshop.com/games/40k/spacemarines/catalog/spacemarines/images/SMRNLandRaider_large.gifA lot of the same elements. Blocky, yet futuristic. Very extreme edge highlights with very dark crevices and shadows.
Another example:
http://us.games-workshop.com/games/40k/tau/catalog/images/battlesuit_cdr.gifThe details seem to serve no other purpose other than just looking really cool. Almost all of the vehicles are completely mirrored.