I'm unable to download Golden Mega from the App Store

Apps in the App Store can only be downloaded when a Developer has submitted the app to Apple for approval. Contact the developer of the app, if you do not see it available in the App Store to download. Any developer can also remove an app, where it will no longer be available or even restrict use by region. That is all up to the developer and not Apple.

Could you please offer more detail? I do not see that offered in the App Store on my iPad. How are you trying to download? What happens when you try? Is there an error message?