With game campaigns seeming to get shorter and shorter, an extensive and deep multiplayer component is a profitable feature, and certainly one of the reasons why the Call of Duty franchise continues to be one of the most played. Treyarch has gone above and beyond in terms of replayability with Call of Duty: Black Ops. The latest bit of content to be uncovered is an unlockable version of one of the first interactive adventure games ever - Zork.

While the title may be unknown to many, its place in gaming history has never been questioned. The game was one of the first text-based adventures that offered an extensive system of user interaction. The game was built on submitting commands to the main character, Zork, while searching caves and dungeons for gems and magical items to claim the title of 'Dungeon Master.'

So what is this game doing in a record-breaking FPS? It turns out Black Ops publisher Activision acquired Infocom in the 1980's, which means they hold the rights to Zork. Apparently, the developers over at Treyarch decided to give the classic text adventure to players as a bonus in addition to the military shooter that fans have already distinguished from its competitors.

Take a look at the video to unlock the game, and the achievement points that come with it:

httpv://www.youtube.com/watch?v=Jkqk8DjPxN4

We've already told you about the unlockable arcade shooter, and now it would seem that a purchase of Black Ops actually netted gamers three separate titles on one disc. Now a new generation of players will have a chance to experience a classic computer game from the 1970's, and broaden their horizons with a genre that may be entirely foreign, given the lack of current text-based fantasy RPG's.

Hopefully these are the kinds of secrets we have to look forward to from Black Ops, and not new game-breaking errors and glitches. So whether text games are something you'll be interested in trying out or not, unlocking both games on the Xbox 360 will net you 35 Gamerscore Points. Let's be honest, we've all put ourselves through worse games for a smaller addition to our score.

If you haven't already picked up  the game, it would seem that you're in the minority. But if military shooters turn you off, then maybe now you'll pick up a copy to spend a little time with Zork. Then take a look through our comprehensive guide to the game, and you'll see that the hordes of players online are nothing to be afraid of.

Call of Duty: Black Ops (Zork Included) is available now for the PC, PS3, Xbox 360 and Wii.

Source: GameLife