If you loved The Island of Giant Insects, try The Island of Giant Insects
A bridge between a film you've already seen and one most people haven't. Here's what they share, and what the second one does that the first one doesn't.
What they share
Both films are directed by Takeo Takahashi, and they both carry the dread mood tag, and they sit in Animation / Horror territory. If that's the register that drew you to The Island of Giant Insects, the second film will land in a comparable space — through a different lens.
dread
What The Island of Giant Insects is
Coastline wreckage steams under a bloated summer sun. Girls huddle around a girl tracing insect wings in the sand, while something chitters beyond the tree line. Less Lord of the Flies, more Silent Hill by way of a junior high biology textbook.

