At first, only the Champion class is unlocked. To unlock the Berserker and Commando classes, you must first sign in with a junk profile that is not connected to Xbox Live. Once you’re signed on and disconnected from the Internet, change your Xbox 360 clock to 2009. Booting up the demo after that will reveal that the Berserker and Commando classes are now fully playable.

Getting the Defender and Bio Engineer classes unlocked takes a little more effort. You basically have to jam the A button as fast as you can while hovering over the locked class and then quickly press right or left to select one of the unlocked classes. If done correctly, you’ll be able to play as the two locked classes, although it may take a few tries. Take a look at this video for more info.

With the five classes unlocked, players can freely check out and test the different class trees, different weapon options, and even find some class-specific epic armor by searching off the beaten path in the demo.