Let's kick things off with the grindingly obvious: there's always been a disparity between how real-life items behave and how they are portrayed in video games. It's highly unlikely, for example, that the next first aid kit you see in real life will be imbued with instant healing powers. It's a safe bet that the next book you read won't immediately be committed to memory after a couple of seconds, with all the useful information handily available from an in-life menu screen. And should your occupation, lifestyle or upcoming shopping-mall-murder-spree require familiarity with firearms, chances are the next gun you pick up won't resemble the science-fiction technology on display in the latest shooter.
Or will it?
Are the weapons that trigger-happy gamers use in Gears Of War, Halo or Fallout 3 really so different from real firearms? We're already seeing games that accurately reflect genuine weaponry in painstaking detail (such as Modern Warfare 2's assault rifles like the FAMAS or SCAR-H, all lovingly adorned with attachments like the Holographic Sight or Heartbeat Sensor, the former of which exists, the latter of which has long been in real-world development). Just as works of fiction once predicted the invention of television and the Internet, games may yet foretell the future of weaponry.
But that's not all - what if weapons in the real world are a lot closer to their videogame counterparts than anyone suspected? Like, right now? What if the ray-guns and force fields and shoot-lightning-from-your-nipples power-potions are already here? Some of them might not be as advanced as the goodies in Gordon Freeman's backpack just yet, but rest assured they will be.
Much of gaming's arsenal to date has been based on tweaking and evolving present weapons to create something much more destructive. Take the Railgun, for instance. Once only considered a hypothetically possible device, it uses electrical current to push a hefty projectile along a pair of metal rails. The design has been around since 1918, when Frenchman André Louis Octave Fauchon-Villeplée patented his catchily titled "Electric Apparatus for Propelling Projectiles". Videogames like Crysis, S.T.A.L.K.E.R and the Quake and Fallout series have had something of a love affair with the railgun - allowing you to splatter enemies with the massive kinetic energy of a heavy metal rod.
The concept of a railgun has remained purely theoretical - that is, until fairly recently. In the 1980s, the Yugloslavian military were working on a railgun-device that reached a projectile speed of 7,000 m/s. The United States has since taken up the mantle - with their most recent 2008 test showing off a weapon that could take down a 5-metre target over 200 miles away. It's due to be ready around 2020, should you like to place your order. Memo to old-school Quake players: when they eventually make a handheld version of this baby, no-one's going to buy all those excuses about 'lag' anymore.