Successfully complete the indicated task to unlock the corresponding weapon:

Akrid Launcher: Reach Career Level 50 with the Snow Pirate Elites.
Energy Gun SP: Reach Career Level 70 with the Femmes Fatales.
Firecracker: Reach Career Level 30 with the Femme Fatale.
Flamethrower SP: Reach Career Level 50 with the Snow Pirate
Elites.
Gun Sword SP: Reach Career Level 70 with the Rounders.
Hand Cannon SP: Reach Career Level 50 with the Rounders.
Machine Gun SP: Have a saved game file from the /Lost Planet 2/
multiplayer demo.
Plasma Cannon SP: Reach Career Level 50 with NEVEC.
Plasma Gun SP: Reach Career Level 30 with NEVEC.
Shotgun SP: Reach Career Level 50 with the Femme Fatale.
Shuriken: Reach Career Level 30 with the Rounders.
V-Device SP: Reach Career Level 70 with NEVEC.