Platinum
Complete the hard difficulty
Complete the epic difficulty
Complete the normal difficulty
Buy all helicopters
Own a veteran shooter
Kill 1000 zombies
Defend the first camp
Kill 500 zombies
Buy your first helicopter
Collect a special paint job
Kill the first boss
Own a fully upgraded helicopter
Escort the first convoy
Repaint a helicopter
Upgrade a helicopter
Kill 100 zombies
Transport a supply to your base
Upgrade a shooter
Hire youre first shooter
Save the first survivor