These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Contested Sequel: Though not being much of a sequel (since Lupin III runs on zero continuity), its glaring difference in tone compared to its anime entries have fans either decry it as a disgrace to its source material or embrace it as being all-round enjoyable.
Some fans have explained it thus: "Cagliostro is a great movie, but a bad Lupin movie."
Fridge Logic: Lupin has his Walther P-38 pistol melted into slag by lasers in one sequence. One can only wonder how the heat didn't cook off the ammunition in the magazine.
Germans Love David Hasselhoff: The movie was a failure on its initial release in Japan for being too cartoony and not having Lupin's adult humor. By contrast, Americans loved it and it's more well-known and sold far better than "Red Jacket" or Mamo. This might be because in the US, it's mostly known for being a Hayao Miyazaki film, so viewers go in expecting something Miyazaki-like (which they will get) instead of something Lupin-like (which it isn't, but that's not a big deal since Lupin isn't too well-known there).
Also worth pointing out that Cagliostro was the first exposure most Americans had to the Lupin franchise, so they had no idea Lupin's behavior was considered out of character.
Moe: Princess Clarisse is popular among fans, was featured in early fanworks and doujinshi, and sometimes even said to be the first "moŽ" character.
Misaimed Fandom: Princess Clarisse was not intended to be the Trope Codifier for moŽ. Miyazaki despises that trope. As a self-avowed feminist, he thinks the concept of moŽ is a terrible fetish that devalues girls.
Vindicated by History: When Miyazaki made this movie, he put his own spin on the Lupin character, toning him down from the raunchier, more manic version depicted in the manga and animated series (apart from the first series, which was also somewhat toned-down since he and Takahata were the showrunners for about 2/3 of it). As a result, it flopped in Japan when it was first released Ė the people who liked Lupin for what it was were turned off, and the people who didn't like Lupin didn't have any reason to watch the movie since no one in 1979 had heard of Hayao Miyazaki. It was only in later years, when Miyazaki gained recognition for his original works and more people watched the movie without any prior Lupin experience, that it belatedly gained a reputation as a classic.