In Lost Planet 2 for the Xbox 360, you can unlock Mark Fenix from the Gears of War series as a playable character. All you have to do is complete the campaign on any difficulty and he will be available.
Also, by beating the campaign you will unlock the use of custom characters in campaign mode which is where he will be selectable. Once you unlock this mode you’ll hit X on the character select screen, and you should see it under the outfit presets on the clothing customization screen.
