Video games are many things: they're a form of entertainment, a way to make new friends and sometimes even works of art.
But they are also technology and - like most tech - they have an expiration date. As gaming advances, it's natural that some old games will succumb to the ravages of age. The process may be significantly slower for many, but even the very best games will eventually start to show some cracks.
In fact, sometimes it is the very best games that get hurt by age the most. You want to remember them for the classics that they were in their day, but then you actually try to play them again and find that they barely retain their former glory.
It doesn't mean that these aren't necessarily good games or that they don't deserve to be remembered as classics. It just means that time has been especially cruel to them.