Maybe this was a localization thing, but interestingly, the game at one point kind of calls you a god (translated and from memory: "you are what humans call a god"). There are also multiple elements in the game that have religious themes: the protagonist's name, Ark, which I always linked to the story of Noah, as it's Ark bringing life to a world that was destroyed, death and rebirth etc. (possibly even thrice, the ending is ambiguous) - also the game is somewhat "anachronistic" to say the least. Also the translation of the Japanese title is roughly "creation of Heaven and Earth".
While the game is technically a bit flawed, story- and presentation-wise it's probably one of my favorites of all time. The subtly eerie setup with everything (e.g. the jingle presenting the acts' titles), man's "emancipation" from nature / Gaia, which arguably caused the catastrophe in the first place, the weird encounters - absolutely fantastic in my opinion.
I’ve seen this repeated a bunch of times but it seems to be an opinion predominantly held by Brits who played Terranigma growing up. I don’t understand it, as I played Illusion of Gaia growing up and love the game dearly (and have replayed it many times since then) but I’ve played Terranigma multiple times and lost interest not long after passing Bloody Mary. The game has gorgeous music and graphics (especially the two world map themes and the early areas) but the story didn’t engage me like IoG.
Yes, Terranigma let you do a lot more different moves in combat which was cool, and the inputs were faster and didn’t involve charging which was a bit annoying in IoG.