However, legacy PC releases often come with modern headaches. If you have dug up an old physical copy of the game or downloaded a digital version, you might find yourself blocked by a prompt asking for a serial number, CD key, or registration code.
If you've purchased the Metal Slug Collection in the past, you might have misplaced your serial number. Here are a few possible places to check: metal slug collection pc serial number
If you have already purchased a physical copy and lost the key, check these common locations: The Jewel Case However, legacy PC releases often come with modern headaches