I don't have all the answers, but, you can extract the PotPlayer installer using 7-Zip, to create your own portable version. This way, you will see both exe's; I think "PotPlayer64.exe" is meant for the Korean/Asian market, as it has chat/social features meant for that market. When you actually install it, in other markets, you will only get "PotPlayerMini64.exe" in the install folder.
If you do extract the installer, you will have to download OpenCodec separately, which you can also extract, and copy to the PotPlayer folder.