I particularly enjoyed the mystery aspect of it, and how the movie directoin subtly pointed us to possible hints and alibis in addition to the dialogue. The red herring was also a nice touch (also featuring a red fish for it), and the whole comical idea of the "masked thief" Deluxe was illustrated comically too, which gave the whole movie an uplifting vibe.
One of my favorite moments of the film also put Doraemon and Nobita's friendship on the spotlight, and this scene (and reprise) also served a great purpose on the whole motivation of the movie.
The music in this movie was more enjoyable than other recent Doraemon films, featuring soundtracks that really fit the mystery theme well, and I enjoyed Perfume's ending theme too.
If there are any drawbacks to this film, it would be some small details that didn't seem to be explained, like Doraemon's replacement cat ring changing shape throughout the film, or what exactly was Dr. Peppler's mistake at the end, or how he snuck into the museum to begin with. Although these didn't ruin the flow of the movie, I did wonder about it after the film ended.
The production team was very adventurous in making a movie focusing on the gadgets you see in the Doraemon series, which risked causing confusion for those who aren't so familiar with the world-building or how some of these gadgets are supposed to work (e.g., Golgon's Head). But they managed to pull off a decent mystery film out of it that kept both the kids and their parents engaged.
