Great Wall 4 is the twenty-third area unlocked in Space Zoo, and the fourth in Great Wall. There are requirements that must be met before the player can unlock it.
Requirements
- Complete 9 additional Great Wall missions following the Great Wall 3 ship upgrade (27 total Great Wall missions)
What is Unlocked
| Great Wall | |||||
|---|---|---|---|---|---|
| Great Wall 1 | Great Wall 2 | Great Wall 3 | Great Wall 4 | Great Wall 5 | Great Wall 6 |