The futuristic yet rugged form of the BattleMech has long since become an icon in PC gaming. Years ago, these gigantic bipedal tanks were ripped from the BattleTech pen-and-paper role-playing game and have since become the subject of a slew of action-packed simulations. The license to BattleTech bounced around over the years until Microsoft finally claimed it--a seemingly permanent resolution. Microsoft has already delivered a couple of solid MechWarrior games, including this year's well-received real-time strategy game MechCommander 2 and last year's MechWarrior 4: Vengeance. The latter game did an excellent job of bringing the world of BattleTech to life--it managed to render mechs with an acute attention to their monstrous proportions. But its graphics weren't its only strong suit, as MechWarrior 4 excelled as a multiplayer game. The game balanced action-packed combat with simulation elements, a combination that pleased many players but still didn't appeal to some of BattleTech's hard-core fans.

The expansion offers five new mechs, including the Black Knight itself.

Nevertheless, the game was successful enough to justify the new expansion pack, MechWarrior 4: Black Knight--which, unfortunately, doesn't tie in with the forthcoming movie starring Martin Lawrence. Black Knight, which requires that you have MechWarrior 4 installed, does introduce a challenging single-player campaign with a dynamic mission structure; a number of new mechs, including the imposing Black Knight itself; and some interesting new multiplayer modes to bolster MechWarrior 4's already good multiplayer options. These additions are sound--they extend and expand on the original game's context in meaningful ways--though they might have given a stronger impression if Black Knight weren't a full year older than, and just as expensive as, its predecessor.

Interestingly, MechWarrior 4: Black Knight was developed by CyberLore Studios, rather than by the same team that did the original game. CyberLore has built up an unusual portfolio for itself over the years, which includes the official expansion packs to the popular strategy games Warcraft II and Heroes of Might and Magic II, as well as its own critically acclaimed strategy game, Majesty--and the expansion pack to that. Clearly, CyberLore knows its expansion packs. It's been making them since before they were in style. Even so, Black Knight is a departure for the company in some ways--it's a graphically impressive fully 3D game, rather than a simple-looking real-time strategy game. On the other hand, Black Knight actually has a lot in common with CyberLore's previous expansion packs, which were technically good but stayed very true to their predecessors.

New environments like this blasted cityscape make for good battles.

The "Black Knight" in the title refers to the notorious mercenary group that you will help lead throughout the expansion pack's new campaign. After fighting for the good guys of the Inner Sphere in the last few MechWarrior games, it's nice to play as the gun-for-hire again, just as you did in MechWarrior 2: Mercenaries, the follow-up to Activision's classic mech sim. Although, as you might expect, the Black Knights won't seem quite as dastardly as they're made out to be, but rather like a typical battle-hardened regiment of soldiers. The game's plot unfolds in some brief noninteractive sequences using the game engine, but mostly through voice-over between characters. The voice work is well done, but alone it doesn't manage to make Black Knight's story very engaging, especially when measured against games like MechCommander 2, which made good use of full-motion video sequences to provide a better sense of context and purpose for the action.

The campaign missions themselves are tough and reasonably varied, and they take you through five operations in a number of colorful environments, from molten wastelands to ruined metropolises to resource-rich mineral fields filled with crystalline outcroppings. The campaign isn't completely linear--the success or failure of certain objectives may yield different options for the next mission. In the mech lab, between scenarios, you'll have a chance to trade salvaged equipment on the black market to get your hands on better gear. You can use this to customize your mechs more than you might otherwise be able to with just the battlefield salvage. But having more options in the mech lab means having an even greater responsibility for custom-tailoring your mech as best you can. The difficulty of some of the scenarios will make you frequently revisit your mech designs, tweaking their loadouts with the prescience of what your enemies will bring to the fray.