[Flashing Green Red. How did ya'll flash twin duck ?]

Did you install java? It's not preinstalled on windows.

I followed this tutorial and it worked perfect for me

[the keys layout of my duck dosen't work]

I guess the keyboard layout of your host machine where you're executing the payload is not the US layout?

Have you specified a language file during the encoding of the payload?

[Different language keyboard]

You could also take a look here, maybe you will find the keyboard layout you're searching for

[Different language keyboard]

The idea is very interesting. Which kind of error message do you receive?

It maybe because the payload in the video in the first line says "Duck translator" without the command keyword REM.

Try these powershell commands which he posted on the GitHub page. The first command

powershell.exe Set-WinUserLanguageList -LanguageList en-US -force;

should set the powershell Language to English.