And then there's the "continuity? what continuity?" school of adaptation. Today's example  of the breed is Macross: Do You Remember Love?
DYRL is a retelling of the Macross storyline in a completely different continuity that nevertheless references many of the key aspects of the original 36 episodes.
I have fond memories of this film, and there are still aspects that awaken that old sensawunda, but time has not been kind to this film.
There were always some utterly cringeworthy elements in the portrayal of Misa Hayase. In DYRL the blatant sexism is beyond belief and I find it hard to believe that I didn't notice it before.
Maybe I've grown up. There's a depressing thought for you. :)
On the upside, the love triangle  is resolved relatively quickly and as a character Lynn Minmei is handled much better in this film than in the series. Minmei is a much more mature character overall, and much less annoying. That she gets slapped here when I don't recall it happening in the TV series is more than a touch ironic.
You still have the "music and love" will save the world (or what's left of it) plotline going on. Then again, those who watch DYRL will know this going in, and the key song this time is very pretty even in the middle of the gigantic space battle.
However it isn't all bad.
There is one very nice touch with Max joining the Meltrandi rather than Miriya joining the SDF-1 (with Max being, ah, upsized in the process). Also Hikaru does begin to both respect and love Misa by the end of the film, and it is clear that the eventual relationship will be a partnership.
There is also the amusement to be had from the otherwise very pretty Haruhiko Mikimoto character designs: ELVES IN SPACE!!!
Once Macross: Do You Remember Love? would have scored an 8 or a 9 out of 10 from me, today it has probably dropped to a 6 or a 7. This still makes DYRL an enjoyable film, but not so much so that I'm likely to upgrade from the VHS copy that I reviewed today.
Day 1 - New Kimagure Orange Road: Summer's Beginning (1996)
Day 2 - Naruto Shippuden The Movie (2002)
Day 3 - Galaxy Express 999 (1979)
Day 4 - Steamboy (2004)
Day 5 - Urusei Yatsura 2: Beautiful Dreamer (1984)
Day 6 - Lupin III: The Castle of Cagliostro (1979)
Day 7 - Howl's Moving Castle (2004)
Day 8 - Ah! My Goddess: The Movie (2000)
Day 9 - Summer Wars (2009)
Day 10 - Macross: Do You Remember Love? (1984)
Day 11 - ???
Day 12 - ???
Day 13 - ???
Day 14 - ???
Day 15 - ???
Day 16 - ???
Day 17 - ???
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Day 19 - ???
Day 20 - ???
 With a 26 episode series running to approximately 600 minutes, cutting this down to 120 minutes can result in the surviving plot being an incoherent train wreck. And that's if you're lucky. Galaxy Express 999 is one of the lucky examples.
 Which in the Kimagure Orange Road example is used to good effect as a character study.
 Another, more controversial, example being the Vision of Escaflowne movie which I don't have but didn't mind that much.
 There is a Macross AMV using Jam and the Spoon's Find Me - Odyssey to Anyoona which is one of the best I've ever seen. It uses a lot of DYRL footage, and there is still enough emotional depth in the love triangle for the song to be appropriate, and for the AMV to work well. Unfortunately it doesn't appear to be on YouTube as far as I can tell.