Gog probably doesn't even bother checking all of the games. The tags are mostly useless, for every game I've checked so far. More tags, but most games have missing or extra/inappropriate tags attached. And, given the way support works around here, not likely to be fixed, ever.
The characters often transform into "dragon mode" during battles. That is as nude as they get. See screen shots 7, 8, 10, and the second animated gif for how that looks. As to sexual content, there's talk and innuendo and revealing outfits. The publishers cover their asses with a disclaimer at game startup (see attached), and gog uses that and the ad/description rather than actually playing the game to fill their tags.
Note that I haven't finished the game, so I may be missing something, but it's not likely given the game's board rating and the lack of a decensor patch (that I know of). If there were censorship, it would probably along the lines of Death End Re;Quest, where the similar bikini-like transformations were considered too risque by some prudes (not censored on gog, though, apparently).