We know what you're thinking: What horrors can be found deep within the noggin of this evil, alien oppressor? The answer, chillingly, is an art book.
The "Helghast Edition" also includes a "Super Voucher," giving players access to a number of bonuses including the soundtrack, a dynamic theme, and a 6.5-inch "Cloaking Helghast" figure.
Special Edition owners also gain access to all pre-order bonuses available at multiple retailers, which include a Retro Map Pack of two Killzone 2 maps, "full weapon and ability access," and "double XP for the first 24 hours of multiplayer." According to the announcement (and some of the original post's comments), the limited edition will retail for $129.99 and will be made available in the U.S. and Canada alongside the regular edition on February 22, 2011.
A European special edition "will not be exactly the same" but Guerrilla promises it "will be great as well." Pre-orders are currently available at GameStop; however, Guerrilla notes that other retailers will carry the product.