Because it's the .lasm file (disassembly). You get the .lua file when executing it. I have explained it in this post:
Why Script Ended:Script Error ? (#cor0fe4l)
From what I see on the video, official version of the launcher that you downloaded from BadCase's site finishes with an error right after you execute it. That's simply because it's not compatible with newest version of GG. Second script that you use is probably from this post. Both official version and this version contain the error of using "W" as second argument to "io.open" function, that is fixed in the file from this post. It should work properly, unless there are some other errors of which I am not aware.
One thing you should understand that the launcher and a script for a particular game are two different scripts. The launcher downloads a script for some game and executes it, everything else is done by the downloaded script. If there is an error in the downloaded script, it has to be fixed and updated version has to be uploaded to the server before you can use it with the launcher. So just wait until the author of the script for your game will fix it and upload to the server.
This video and screenshots clearly show that modified version of the launcher works fine for you, while the error occurs in the script for the game.