Our Weapons Will Be Boxy In The Future: Averted in most cases; most guns, while still being fundamentally gun-shaped (ergonomists cringe at the thought of trying to actually hit something with the remote-control-styled ST:TNG phaser, for example) as appropriate to the manipulators of the species they’re designed for, still follow The Aesthetics of Technology in being sleek, curvy organic shapes.  After all, they’re nanofactured – grown, not assembled – and all the field-replaceable parts are modular, so…

Played absolutely straight in just one case by the S-11i Mamabear heavy sluggun, because the Mamabear is a brutally overpowered weapon designed – well, the designers appear to have been thinking about building a weapon to fight kaiju at close range. It looks like a large vaned metal brick with a stubby barrel sticking out of one end because that’s precisely what it is; the mass driver is sufficiently overpowered that the whole mechanism of the thing is built into a giant heat sink to keep it at something close to a reasonable operating temperature. Although if you fire the thing multiple times in close succession, reasonable operating temperature means “only radiating in the red”.

(It has some other disadvantages too, like small magazine size, slow reloading rate, inaccuracy at long range, and a recoil that inflicts compound fractures on anyone who fires the thing whose bones aren’t reinforced with hard-wearing synthetic composites, but sometimes that’s worth it for the ability to one-hit kill damn near anything you’ll ever find yourself staring down the barrel at.)