The first thing that may annoy a Red Garden series viewer are the personality changes in the characters. If you can't deal with that I'd recommend not watching this OVA. What would next annoy a Red Garden Series viewer is that after having the contact information of their friends and family on their person at the end of the series they claim to know nothing about their past in the OVA. My mind kept drifting away due to this plot hole in that even if they lost the information their still living friends and relatives would have found them somehow. Lastly, perhaps to keep Red Garden series viewers comfortable or out of necessity, many characters from the series appear as different people in the OVA. I say it's a little bit of both.
I guess I mostly fell in love with the OVA due to its strange familiarity. I liked seeing the characters I knew as completely different people and in a strange yet familiar setting. In that way people who just jump into the OVA without having seen the series wont get that affect. Then for those who have seen the series the strangeness may be a complete turn off and the familiarity seen as tarnishing their image of the series.
