Full version features:

• Couch co-op action! Grab a friend, sit on the couch together and blow stuff up!
  
• Singleplayer experience: switch between characters and command your AI ally to wait behind or follow you into action!
  
• Procedurally generated mission levels give unlimited re-playability
  
• 5 different environments, with variations within each
  
• 5 enemy groups, each with 5 tiers of units to unlock and fight
  
• 5 difficulty levels to match your play style, from casual to hardcore

Demo version features:

• Singleplayer experience: switch between characters and command your AI ally to wait behind or follow you into action!
  
• Procedurally generated mission levels give unlimited re-playability
  
• 1 environment, with limited variations
  
• 1 enemy unit from 1 enemy groups
  
• 5 difficulty levels to match your play style, from casual to hardcore