Honestly, I think the script can only be justified within video game standards. It can appear good but only because video games have had such a knack for horrible writing in the past; if we put it alongside any measure of quality writing in literature or any other medium it kind of falls flat on its face.
I mean come on, Carmilla actually says "We're not so different, you and I". (i don't remember if it is verbatim, though: it may be slightly altered)
I would really like to provide specific examples here (I remember that narrative about dreaming being terrible, though), but I'm running up against the clock and I really must be reading some Kant right now.