The Commando contains a special savefile that lets you battle zombies with some great extras:

• $500 and Techgun from the start
  
• $100 and Uzi after world 1
  
• ???? after world 2

To make sure you’ve installed our DLC properly, go to your Steam client and click on:
Boobs vs Zombies > Properties > DLC

To use the DLC click on:
Boobs vs Zombies > Properties > Local Files > Browse Local Files