SirPrimalform: I don't think it's legal 
any of the time. The legal equivalent of abandonware would be public domain I suppose. 
 AacRrc: Well a copyright on a video game can't have run out since video games aren't old enough  
 Edit: Apparently I can't spell 'video game' 
 No, but the person owning the copyright can make it public domain if they want to.  
 The point I was trying to make was that the very definition of abandonware is something that's still in copyright and the copyright just isn't being enforced. Legal abandonware isn't abandonware. :P