In my honest opinion this is more of a preview or a commercial than anything else. Scenes switch so fast without any explanation that it is next to impossible to tell what is happening unless you have watched the show like I have. In fact, it appears they squeezed the first 2 episodes into this 8 minute long ova. So if you think about it this is just pretty much an 8 minute long trailer.
So overall I rate this trailer a 3, simply because I feel this wasn't meant to be watched as anything other than a preview; if it was the actual anime adaptation I would have given it a 1. It does serve its purpose as a preview though and I'm sure if you were a Mirai Nikki fan before October 9, 2011 this might have been cool to see, but today it serves no real purpose.
