If you cannot hear the BGM and sound effects,

please check the sound option at the Setting in the game.

■ How to Set Game Sound

- [Settings] > [System] > [Sound] > [BGM/Sound Effect]

If you still cannot hear the BGM and sound effects after turning all the settings on,

it may be caused by several files being damaged while downloading the game.

So although it may be tedious, 

please delete the game completely and then reinstall the latest version.

■ How to Delete the Game (AOS)

1) [Device Settings] > [Application Manager (Application Program)] > [Gunship Battle: Total Warfare] > [Delete Cache, Data] > [Delete] 

2) Connect USB or use the ASTRO app to check if the folder below is deleted

* Folder to delete: [com.joycity.gw]

* Folder location: [Android] > [Data] > [com.joycity.gw]

3) If the folder still exists, delete it and reinstall the latest version.

※ The steps to delete the game can be different depending on the device.