As you defeat these enemies and progress through the game, you'll open up plenty of new upgrades for your character. (useapotion.com)
These units can produce new upgrades for you to use in the field including weapons, tools, and support vehicles. (cogconnected.com)
It combines everything great from the original and steps it up a notch with new upgrades, amazing graphics, great co-op play and an overall great game. (darkstation.com)