Spoilers For Final Fantasy VII Remake Ahead!
Final Fantasy VII received a number of prequels, sequels, and spin-offs after it was released, all of which added to the story in some way. Final Fantasy VII Remake made several references to these spin-offs, including one near the end that will baffle people who have never played the original game and are going in blind.
In Final Fantasy VII, it's revealed that Cloud Strife's memories had been messed with and that he never joined SOLDIER. He had confused his memories and his personality with those of a member of SOLDIER named Zack Fair. Zack would go on to star in a 2007 prequel game called Crisis Core: Final Fantasy VII, which offered a look at the original incarnation of SOLDIER and the events leading up to Final Fantasy VII.
Crisis Core was released for the PlayStation Portable and fans have been expecting some kind of HD remaster in the run-up to the release of Final Fantasy VII Remake, but so far, Square Enix hasn't budged. There is a prominent scene involving Zack in Final Fantasy VII Remake that won't make any sense to new players, so the time is right to bring back Crisis Core in either a remastered form or as a full remake.
The combat system in Final Fantasy VII Remake is closer to that of Crisis Core than it is the original Final Fantasy VII, so it's possible that a remake of Crisis Core could use the same engine. The difficulty would need to be balanced around only using a single character, or the story could be tweaked to have Zack fighting alongside Shinra troopers, members of SOLDIER, or the Turks at different points throughout the story. Crisis Core was developed for a portable device, so its mission-based structure lent itself to short bursts of playtime, but a remake could expand his adventures into longer quests, in order to make things feel more cohesive. Crisis Core was one of the PSP's best games and it's a shame that Square Enix hasn't updated the original game for PS4 or Steam, but there might be a legal issue that is holding it back.
The main issue with remastering Crisis Core is Genesis, and we're not talking about how he's an awful character who deserves to be scrubbed from the series. Genesis' appearance is based on a singer named Gackt, who even voiced the character in the Japanese versions of Crisis Core and Dirge of Cerberus. It's possible that Genesis would need to be changed so that Square Enix could avoid any potential legal issues with Gackt, so his appearance would need to be overhauled. If this was the case, then the FMV sequences would need to be redone, and couldn't just be cleaned up for an HD release, which might be more work than Square Enix is willing to put into the game.
It's strange that Square Enix would reference Crisis Core in the ending of Final Fantasy VII Remake when it can't be played on modern systems without relying on emulation. The time is right to remake Before Crisis and to either remaster or remake Crisis Core, so that fans can understand the entire story of Final Fantasy VII Remake without needing to resort to online guides.
Final Fantasy VII Remake is out now for PlayStation 4.