Underrated gem among the Lupin III series. Don't pass it up. Bad stuff first: Plot-wise, this is a pretty average Lupin movie, it's got the standard cast of forgettable side-characters, a very straightforward quest for treasure, and a generic villain with generic evil motives. There's a bit of awkward pacing too, with really fun action sequences being separated by sequences of characters literally just walking around a cave. If you've seen Castle of Cagliostro, then this will come off as a weaker retelling of the same ideas. Audio here is below average, unfortunately. The soundtrack doesn't have any memorable tunes, and a lot of it feels kindof inappropriately silly, rather than cool. The typical voice cast isn't here either, but that didn't bother me, personally.

Fortunately, this movie more than makes up for what it lacks by being the best looking entry in the series. This movie is made up entirely of jaw dropping car chases, intense fight choreography, and solid character acting. There were no corners cut here, you get to see every building fall apart in full detail, and it's incredible. I especially loved the chase scene in the middle of the movie. There's a lot of really good visual gags too; for example, when Zenigata's cars are run over by a train, you see his officers all crammed into one car chasing after Lupin.

This movie's setting is also good. A lot of Lupin movies take place in "Somewhere - Europe", rather than any specific locations, but the town in this movie has a lot of memorable set-pieces, and you can things about the setting while watching (it's got a lot of trains, for example). It's not quite as distinct as Cagliostro, but it's still good. Would've been better if less of it took place in a cave though.