Im not sure why i want to do this by i find it annoying to have to reinstall a game with every new computer and console ive gotten over time. How would one make a offline installer or backup, I would also want to make them look like retro media if possible.
By chance are there better ways of re installing games without torrents?


You can just use a USB. Cloning your directories and copying them over is how backups work. Copying the files over as they belong accomplishes installing the game.
Cloning on Linux
Use the rsync command in Bash to clone directories.
rsync -avh /path/to/source/ /path/to/destination/
Replace /path/to/source/ with the path of your game directory. Replace /path/to/destination/ with the path to where you want to clone the directory.
On Windows
You can use PowerShell
Copy-Item -Path “C:\path\to\source*” -Destination "C:\path\to\destination" -Recurse
Replace C:\path\to\source\ with the path of your game directory. Replace C:\path\to\destination\ with the path for where you want to put the files. Probably the USB
Due to how they are affected by Bit Rot, I would bot use any kind of flash based media (USB Flash Drive, SSD, MicroSD, etc) for any kind of long-term backup.