Watch the original films or the remakes, they are all better than this cross over. This one is too rushed to pull you into the stories and the action between Sadako and Kayako is practically non-existent. The actual action between them was probably around 3 minutes long and most of that is just them staring or walking. The ending was, imho, the most uninteresting option they could have taken. Clearly a cheap money grab which is one reason why Japanese film, anime and games are on a decline. It used to be about quality and originality in the 80s and 90s but since then it has been a in your face money grab and they don't even bother to hide it. When anything becomes popular, they ruin it in time (a bit like Star Wars here).
Review of Sadako vs. Kayako
