While it does contain some humor and cute side plots, for the most part, the movie is a serious exploration of two aspects of death, one familiar to American audiences another rather uniquely Japanese.
The first (familiar) problem is the death-with-dignity issue. Should every last conceivable attempt be made to extend the life of a hopelessly terminally ill patient? Even at the expense of intensified suffering of both patient and family at the end of life?
The second (uniquely Japanese) question is whether the doctor and family members should be candid with a terminally ill patient about the true nature of his illness. Until fairly recently (like the late 1990s) both the Japanese medical community and Japanese society in general were firmly convinced that it was better to try to keep the patient hoping for recovery for several reasons, among them that sometimes the patient's own hope can be more powerful than the most advanced efforts of Western medicine in curing the patient.
The handling of these two themes is graphic and intense. The portrayal of the medical treatments is incredibly technically detailed as well. The performance of Masahiko Tsugawa as Dr. Ogata is extremely convincing and among the best work of this actor's career.
Towards, the end of the movie, the effects around the patient's out-of-body experiences are also extremely creative and technically superb, even by today's standards, much less for 1993 before the advent of digital-everything.
There is also a superb sequence of one of the key Buddhist sutras set to classical music towards the end of the movie as well.
Overall this is a good movie. However, if you are looking for a light-hearted romp along the lines of "Tampopo" this movie is not for you.