XCOM: Enemy Unknown, one of our most anticipated PC games of the year, is officially available for preorder at various online outfits, including Steam, which is spicing things up with a unique bonus system. These days, it's common for companies to reward customers with extras for buying games before they launch. This is usually a straightforward affair: pony up and you'll get something along the lines of special weapons, characters, cosmetics, concept art, a soundtrack or other goodies.

Instead of offering a flat bonus, Steam has gamified the process with tiered rewards that the community can collectively unlock by purchasing XCOM. As of writing, nearly enough people have preordered the game to unlock the first reward, an "Elite Soldier Pack" that includes a classic XCOM solider inspired by X-COM: UFO Defense, as well as two aesthetic upgrades: complete control over the color and tint of all armor sets, and "soldier deco packs" which provide several visual tweaks to armor suits.


The second tier will earn preorder customers three exclusive XCOM-themed Team Fortress 2 items: a flattop haircut-styled hat  ("The Crafty Hair"), an alien head hat ("Area 451"), and a special pin ("The Vigilant Pin"). The third and final reward tier is simply a free copy of Firaxis' Civilization V (it's giftable in case you already have it). It's unclear how many preorders are required to unlock these perks (the first one has reached 87% in under two days), but the community has until October 9 when the game releases.

With the launch only a few weeks away, 2K and Firaxis have revealed XCOM's system requirements. At minimum, the game calls for a 2GHz dual-core processor, 2GB of RAM, 20GB of storage space, a DirectX-compatible sound chip and a GeForce 8600 GT or Radeon HD 2600XT with 256MB of video memory. However, the developers recommend that you play with at least a 2.4GHz Core 2 Duo or 2.7GHz Athlon X2, 4GB of RAM and a GeForce 9000 or Radeon HD 3000 series graphics card with 512MB of memory.

Set on modern-day Earth, players control the commander of a top-secret military organization known as the XCOM Project, which is tasked with addressing a hostile global alien invasion. Unlike the XCOM shooter being developed at 2K Marin, Enemy Unknown stays true to the franchise's strategic roots. In fact, it's said to be a reimagining of 1994's X-COM: UFO Defense, and considering Firaxis' reputation when it comes to strategy games (namely Sid Meier's titles), Enemy Unknown seems to be in good hands.

Along with fancier visuals such as higher-res textures and greater zoom levels, PC gamers will enjoy various gameplay benefits over the console version of Enemy Unknown. "There's more upfront information," according to lead designer Jake Solomon. "The game isn't tile based, but when you’re playing it [with a] mouse and keyboard it's just irritating as hell to play a tactical game without a grid. We actually ended up overlaying a grid on the PC version of the game," he explained.

XCOM: Enemy Unknown gameplay walkthrough with lead designer Jake Solomon

PC players will also be able to take advantage of the grid in what Firaxis calls Enemy Unknown's "tactical view." "It's really minor," Solomon said, "but when you hold down the right mouse button it'll lay a grid over the entire world, which is kind of nice for flanking and determining line of sight and things like that. And in the PC version you can mouse over the alien heads and the camera will scroll to them, but it'll also tell you everybody’s two hit percentages just right there on that first screen."