Playing an FPS like a sneaky, underhanded rat will never be as rewarding as in Deus Ex: Human Revolution, according to the above developer diary, titled "Stealth." Deus Ex devs delve into the secrets behind sneakery, which include a cloaking device, x-ray vision, silenced snipers and a crossbow, and suggest players eavesdrop on guards' conversations instead of shooting them at first sight.

Deus Ex already offers up to 40 hours of gameplay, but crawling on the floor and crouching behind every box you see might just bump that number up to 80. Or 800, depending on your crawl-speed.