The thing is that the original also took place in Spain yet they talked Mexican Spanish for some reason

I'm not sure how to describe it, but the entonation is quite different, and some words change too. It's like UK english and US english to say the most common varieties of english.

As someone from Spain and considering the game happens in Spain yes, I'm kinda tired Americans mistake both groups

Haven't played it, do they still talk in Mexican Spanish or Spain Spanish?