If there's a better or more commonly used term for this let me know, but my idea of an "expired classic" is a game that was acclaimed and beloved at the time of its release but that would be nearly unplayable or unacceptable by modern standards. Not just less impressive or weaker, mind you, but outright bad. Think "aged poorly" but like, REALLY poorly.
The quintessential example is Goldeneye 007. While absolutely landmark for its time, gamers that pick it up now would likely be baffled by its controls and appalled by its significant, unforgivable framerate issues. Even some people that used to love playing it have a hard time enjoying it now (myself included). It is a game that has "expired" over time.
The expiration doesn't have to be due to technical issues either. It could be due to cultural issues, design issues, or any other factor that makes the same significantly less palatable today, even to those that want to play it!
What are some other examples, and why have they expired?