Never knew that Amazaon JP was that bad but at the same time seeing how some review stuff even on the german or englisch Amazon I should not be surprised.
I remember reviews for games where they gave it one star just because the delivery was bad. Most of the time I do read some of the bad ones and the five star ones to get a feeling, but for me the most accurate ones are those inbetween. (People just more often imo give reviews when they are disappointed with something. At least I do post such amazon reviews more when I either was totally amazed by it or if it was bad, the rest mostly gets nothing for me because I cant be bothered to do that...
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I am also not sure if they changed it but as far as I can remember, as long as you are logged into amazon you can write reviews to anything, even stuff that you dont own.
And taking in the knowledge that Amazon JP is way more negative:
1.189 people have given their votes. 29% of them have given it full five stars and 16% four stars. Thats 45% of the reviews. 18% are in the middle of it with three stars and 37% are either two or 1 stars. So at least 63% were quite fine with it. So even for that site its not that bad imo.
To compare it, the english Amazon, it has less votes, half a star more and most of the people seems to be quite happy with it. 61% gave it a five star rating, 10% each for four and three stars and 19% for two and one stars together. So at least 81% of those that put a review there were still fine with it.
Of course that rating should be taken with a grain of salt because I saw some that posted five stars with the message that people should stop giving it 1 or two stars for stupid reasons and then I saw some one stars that gave it that because the disk was broken or they did not get their codes..which has nothing to do with the game at all.
But of course I would be interested in how other sites are seeing this but imo I doubt that most are truly hating the game.