Last month, the Software Preservation Network (SPN) made arguments in support of a Digital Millennium Copyright Act amendment that would allow libraries to bypass digital locks on video games so that academics and credentialed researchers could study them. But the games industry is fighting back.
History.
Lol
Not a joke though, following how certain game play mechanics changed over time, how interfaces changed, how that change was affected by new hardware, etc. I mean, I've never been good at FPS's but I played the crap out of Doom and Doom 2 but after playing other FPS's that were based around being able to use the mouse to look around it is physically painful to try to go back and play Doom.
There's a ton of games that were not huge hits but had some new combination of genres that were mind blowing. People have heard of System Shock, but who remembers Cyber Mage?
Hell, there's YouTube videos of people literally tearing apart the code of NES games to figure out why the underwater section at the dam was so difficult in the first Teenage Mutant Ninja Turtles game. Finding where in the code the hit boxes were described and finding out that hit boxes (invisible) don't always follow the visual logic of the sprite graphics.