Any praise this movie gets is mostly for the last 30 minutes, because the first half is a weirdly done recap/rehash of the series.
Basically this should have been a special epilogue type episode, instead of an hour long movie. The first 10 minutes recap the series, but is not needed because if you don't already know the ins and outs of the 13 episode series you'll be completely lost regardless of the recap. The next 20 minutes are a mix of alternate takes from Suwa's pov or scenes with him that were talked about in the series, just not shown (and they honestly could have had this 20 minutes as an episode in the series, it would have fit perfectly after the episode were it ends on a cliffhanger that he too has a letter too).
The last 30 minutes show us how they sent the letters as well as showing us what the alternate future looks like, although it's odd how they handled that because they then imply it was just a dream Suwa had, but then also reveal that Naho had the exact same dream, implying they are leaving it open ended to viewers to decide but then show so much of that alternate future they may as well have not bothered with the scene talking about dreams.
Overall the last 30 minutes give a better conclusion then the actual last episode did.
