The Key visual novel, "Little Busters!", has some additional routes in its "Ecstasy version" with two new heroines. These new routes weren't translated back then, which was why I didn't get to play them when I first played Little Busters. Now that they have been translated, however, I'm still unaware of how these new routes are accessed, and whether if they would require me to replay the whole story or not. If so, then it's a good example of why playing a partially translated VN is a bad idea, particularly for lazy people like myself who aren't willing to go back years or even decades later to reread the whole thing just for some hours of additional content.
This applies to Chaos;Head as well, of which its remake, the untranslated "Chaos;Head Noah", contains additional routes and heroines as well. Given what has happened to my relationship with Little Busters, I think I'm rather glad that I didn't ruin my reading experience by prematurely playing its original translated version. Maybe it's just a way to comfort myself in knowing I haven't got to experience such a popular VN, but if so, then so be it, I'm comforting myself 'till the remake has been translated in one or two or even three years.
Of course, none of this matters if the additional routes are selectable in the main menu, and you could just immediately access them... but I highly doubt that. Most VN routes like this usually require you to unlock the True End first or something like that.