So I'm talking about games that are on dead consoles/systems and for one reason or another, are difficult to play or will become difficult to play.
When I say difficult to play, I mean because a re-release doesn't exist on modern hardware and emulation of said games is very difficult.
So for example, pretty much any Mega Drive game isn't an issue, since emulation for 16 bit machines is a cakewalk and anyone will be able to play the games for years to come. Games on the Xbox original though are much harder to play as without the original hardware it's not possible to play the games as intended (maaaaybe with a 360).
Another recent example was Grim Fandango, now remedied by the remaster. That game was very difficult to find legally, and had all sorts of potential issues running on modern hardware.
Here's a list of games I really want to see get released onto Modern PC/Modern Consoles:
Jet Set Radio Future
Panzer Dragoon Orta
Ninja Gaiden Black
All three are OG Xbox games, and OG Xbox isn't getting emulated any time soon, sadly. We're probably more likely to get Xbox 360 emulation before the original. I believe these all work to an extent on Xbox 360, but that console is going to fade out of use soon too, already replaced in many homes by the next gen.
JSRF is one of the best platformers I've ever played, and people love the original's re-release. It would be a true shame not to see the sequel get the same love.
Panzer Dragoon Orta is a game that is also well loved by it's niche audience and seems to have issues running on 360 emulation too (in my experience sadly).
NGB is one of the best action games EVER, some say THE best of all time. Any yet it's relatively so hard to play.
These games would all be amazing on PC or new consoles, and I really hope it does happen.
Panzer Dragoon/Zwei/Saga
Thanks to Sega 'lol lost the source code!' these are going to be difficult to port, but I really think someone should take the time to either reverse engineer them (unlikely) or come up with some way of emulating them perfectly for a re-release.
These games are such an important part of Sega's history, to let them become expensive collector's items only playable on decades old hardware would be sad.
Saturn Emulation DOES exist, and it's not bad, but it's also not perfect and many games have issues running on emulators due to the Saturn's bonkers architecture.
Any other games you can think of? I'm thinking this forum will mostly be Saturn/Xbox originals which are the two most obvious I can think of. There's also a number of old PC games that are very difficult to run nowadays, off the top of my head is Blood. Some arcade games might also be contenders, as well as Dreamcast (although I expect DC emulation to improve in leaps and bounds in comparison to something like Saturn).