You enter the stage full of zombies on the portal.
Hang in there until the next portal opens against zombies

- Select the avatar and stage from the lobby and proceed with the play
- The portal opens when there is 15 seconds left of the timer
- If you don't enter the portal, the game is over
- Once you clear the stage, you can choose the next stage
- The more zombies you kill, the more items and experience you get