Unable to download Golden Microphone from App Store

You would need to contact the developer of the app. From your screenshot, the app was available 16 years ago and it would not be unusual for the developer to no longer support the app in the App Store.

Not sure if this is the same developer, but if it is they may have replaced that app with a different one. You can view the information on the website here and also use the link to view it in the App Store. Developers can also restrict sales of their apps by region, but I can confirm that this app is available in the US. Good Luck!

https://megaphone.smudge.com/index.html

The screen shot shows an app called "Megaphone", not "Megaphone Golden Microphone."

There is an app called "Megaphone" in the U.S. App Store, which runs on iPhones and iPads. It requires iOS 10.0 or higher. The icon is different from the one shown in your apptopia Web site screenshot.

Mac Jim ID has already posted a link to the developer Web site.

If this is not the app that you had in mind, or the developer is not offering this app in your country, I don't think there is much that we can do about it.