The Castle of Cagliostro is much superior, whether in animation, art, script and history; it's a more familiar and enjoyable.
In this film Lupin is more faithful to the manga, acting like a more malicious guy, different from the gentle and gentleman version of Miyazaki. Characters like Jigen, Goemon and Fujiko gain more prominence in this film. Lupin's dynamic with Fujiko is a lot of fun, with her always seducing him and always ending up being cheated on by her. There are very sexual scenes, with lots of heavy adult jokes, plus shootings and a dark and violent tone.
The problem in The Secret of Mamo is in the plot, which mixed an action / espionage with a misplaced scientific fiction, becoming a complete mess as it advances, with Hitler pops up out nowhere and then culminating in the most bizarre and cringe ending I've ever seen with a giant brain floating in space.
