Takahashi Meijin no Bouken-jima IV

Master Higgins and his lover Tina were having a good time with their dinosaur friends on the peaceful Adventure Island. One day, suddenly a suspicious shadow appeared in the sky and kidnapped the dinosaur friends one after another. The animals of the island were brainwashed by the suspicious shadows, and the terrain of the island was completely changed. Master Higgins embarks on an adventure to rescue the kidnapped dinosaurs and restore the peace of the island.

Adventure Island IV marks a notable departure from previous games in regards to the gameplay, ditching the linear arcade-style platforming in favor of a more open-ended, exploration-oriented game with light RPG elements, more closely resembling later games in the Monster World series.