The sequel to Mechwarrior 4: Vengeance. When you're a 'Mech Mercenary, you call the shots. You don't fight for honor - you fight for cold hard cash, a fierce reputation, and the heart-pounding thrill of the kill. Your allegiance goes to the highest bidder. You answer only to the call of fortune. Your fate is in your hands alone. Select from 4 of the most notorious mercenary units, Kell Hounds, Wolf's Dragoons, Northwind Highlanders, and Gray Death Legion, to alter your missions, with different outcomes based on your victories. Choose from over 35 different 'Mechs, including 10 new ones. And for the first time ever, your secondary lance allows you to muster 8 'Mechs into battle simultaneously. Or make a killing in the infamous Solaris VII arenas, where fighting dirty can make you filthy rich. Includes 'Mechs from the Black Knight expansion for Mechwarrior 4, and is fully compatible with Mechwarrior 4 'Mech Packs. Fight for fame. Fight for fortune. Fight as a Mech Mercenary!
On July 9, 2009, it was announced that MechWarrior 4: Mercenaries would be released for free by Studio MekTek. Shortly after, the company stated that Microsoft's legal department held up this release. After Microsoft gave the project a go on April 22, 2010, it was finally released on April 30, 2010. MekTek thanked its partners Smith & Tinker (the developers of MechWarrior 5), Virtual World Entertainment and Catalyst Games (the current owners of many of FASA's tabletop games, including Battletech, on which the MechWarrior series is based) for "pressing Microsoft to allow for the release."
The free release includes all of the original content, as well as additional bug fixes, features, and Battlemechs. A link can be found in the Links/Searches section.
There are three different endings. Which one the player receives depends on which branch of the campaign they take (i.e. join House Davion, House Steiner, or remain neutral).