There's been a few threads about CT and FF7 connections (as previously linked) but frankly, I don't see much my way of connection between the two. I do, however, see a lot more connection between FF7 and CC. I've mentioned that I'd seen these connections before, and ventured to offer to post the connections, but I never did. So, I'll do so now.
FF7 - Cross comparison
Most obvious:
Materia -> Elements:
A customizable magic allocation system, with strategic benefits in even the placement of each piece, that includes elemental magic, attack abilities, and summons. Both even have a limited effect use per battle. Both are technological advancements designed to draw from a connection to the planet, and both have a story episode of being stolen. Plus, both play a key factor in the one chance each team has to avoid the games' crisis, and the completion of this plan is largely made possible by contributions made outside of the playable characters (Bathesar -> Aeris, after she died)
Outside of having to use the main character, each other playable character's only unique contribution to battle lies in a few unique special abilities. These abilities aren't limited to being just direct damaging attacks. (techs vs limit breaks)
Characters: Protagonists.
Young men that have two factors of identity crisis as part of the development of the story. Both have identities that are 'dead' and need a process of recovery to getting back to being themselves. Both are involved in a love triangle between two playable characters, with the 'new' girl friend effectively winning out. The identity crisis, and a key portion of the plot for both characters are tied to dark protagonists that influence several years of life to both characters, effectively making them who they are for the course of the game. (Sephiroth's gene's make Cloud into a solder, screw with his memories, and even delve him over the edge into mako poisoning. Serge's
father steals Serge's identity) Furthermore, both lead characters have the key factor needed to bring up the ultimate destruction and share a connection to the end boss.
Other Characters:
Leena -> Tifa: Original girlfriend of the main character. A promise made to said gf plays a key factor in the progression of the story. (Serge's hunt for the necklace shells leads him to the connection to Another World, Cloud enlists in soldier)
Cait Sith -> Harle: A jester character who's identity isn't what it seems to be. Their spying leads the main party into conflict with each spies corresponding party (Cloud fights the Turks, Serge the dragons)
Kid -> Aeris: New girlfriend that plays a large role in the setup and conclusion of the game's story that also need to be rescues on more than one occasion, and even have a cinematic death scene.
Sephiroth -> Linx: Antagonists of the story that are dark in character, use unusual weapons, challenge the identity of the lead character and use each corresponding hero as a means to further their plots based on utilizing each characters identity. Both villains have a cinematic scene as a result of them burning something, and also another scene where they stab a significant playable character.
Other connections:
Each game's hero group has a conclusive battle with the developers of the games technological fathers of that games system of magic (Draconians vs Shinra)
The pursuit of and actions taking accordingly on behalf of stopping/fighitng one villainous group leads to the reveal of another group that are fought through a systematic process of boss fights. These new bosses also share a connection with the planet and are distinguishable by their color. (Dragons vs Weapons) One of these particular fights in both games is capable of being concluded outside of combat. (Niki's concert vs the Sister Ray)
The planets in both games summon these extra bosses as a means of balance, and/or defense. (draconian timeline pulled into counter balancing chronopolis, weapons are summoned because the lifestream is being culminated)
The primary/most dangerous antagonist to the story envelops itself in an otherwise inaccessible area that they use to hide/protect themselves while they grow into destructive fruition. This boss is a merge between a human and an alien being from another world.
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I could post more, but that's already pretty lengthy and I think is a good summary base for just how much I find the two games overlap.