Kind of a shame that KIU doesn't have the option to switch to Japanese language and voices because it's difficult to find playthroughs of that game in Japanese and the few I have found have commentary on top of the voice acting, which ruins my intentions.
Dark Pit's down taunt in Smash is an allusion to the "Pre-Boss Battle Rallying Cry" he and Pit do at one point in the game. He says "死にたい奴は前に出る。" in the Japanese version. ("Anyone with a death wish, come forward!", officially translated as "Anyone who wants to die, step right up!"). Seems the Smash translators missed that detail since he just says "Game on!" in the English version.
They also messed up in some of Lucina's quotes, making her sound out-of-character in those (though the trailer did capture her and Robin's personalities quite faithfully). Literally, the translations are well done, but the tone of voice was overlooked, so the connotation changes.
When playing Bravely Default and noted the game had the option to put both text and voices in Japanese, I started wishing more Japanese games had such an option in the localized versions. It would help me learn the language a lot for sure, since that was the exact same method I used to learn English (along with classes, of course, but I do plan doing a Japanese course later this year).
I might be doing a Bravely Default walkthrough entirely in Japanese (text and voices) when I get more used to the language.
