Collect resources and build your first shelter room.
Fight against zombies and defeat the 10th stage.
Unlock your first soldier.
Unlock your first gun.
Collect and unlock every single gun.
Collect and unlock every single soldier.
Upgrade your shelter and unlock the 4th room.
Upgrade your shelter and unlock the 6th room.
Move on and try to beat the boss in stage 100.
Fight more zombies and complete stage 50.