Prehistoric Isle in 1930 (Genshi-Tou 1930's) is a horizontally scrolling shooting game developed by SNK and released in arcades in 1989.
The player takes control of a biplane armed with a forward-firing machine gun. It can also be equipped with an option weapon pod that can be rotated clockwise around the craft. The option's attack changes depending on where it is currently positioned:
- When directly above or below the plane, the option fires energy waves that reflect back upon contact with a surface.
- When diagonally above the plane, the option fires balls of energy that bounce off surfaces at a 45 degree angle.
- When diagonally below the plane, the option drops bombs.
- When directly in front of the plane, the option replaces the default machine gun with its own flame cannon.
- When directly behind the plane, the option deploys aerial mines.
Ships have been mysteriously disappearing in the vicinity of the Bahamas for years. Now, in 1930, the United States government sends an expedition to the area in a flying boat to determine the cause. As they survey the ocean, the expedition comes across an uncharted landmass which they dub "Greenhell Isle" and launches two reconnaissance biplanes to take a closer look. As they investigate the island, the biplanes come under attack by dinosaurs and other life forms that were thought to have become extinct millions of years ago.
Inquiry 1 - Forest
The biplanes make a low pass over a tropical rainforest, battling dinosaurs, pterosaurs, prehistoric wasps, and Neanderthal men.
length: 116 feet
weight: 150 tons
length: 93 feet
weight: 5 tons
Inquiry 2 - Airborne
In this short stage, the aircraft make a high-speed and high-altitude flight across Greenhell. The pterodactyl and insect enemies are joined by Neanderthals improbably hang gliding from giant bats.
length: 100 feet
weight: 1 ton
Inquiry 3 - On the Ground
Flying through a canyon and observing the remains of still more ancient life forms, the pilots face markedly more ferocious attacks. Strange creatures strike with their inner jaws and ichthyosaurs leap from the river bed.
Unknown Dinosaur (mini-boss)
length: 200 feet
weight: 70 tons
Ancient Coleoptera (boss)
length: 100 feet
weight: 0.8 tons
Inquiry 4 - Bottom of the Sea
With their craft equipped with canopies and ballast tanks to convert them into makeshift submersibles, the expedition descends into the Atlantic Ocean. The sea around Greenhell teems with vicious prehistoric life. The somber sight of dozens of shipwrecks confirms the fate of those who entered these waters.
length: 106 feet
weight: 25 tons
length: 140 feet
weight: 10 tons
Inquiry 5 - Underground
After surveying the surface, sky, and sea, it falls to the expedition to enter the voluminous caverns underneath Greenhell. Amid the magma flows, the tyrant lizard king awaits...
length: 133 feet
weight: 50 tons
length: 426 feet
weight: 200 tons
Their investigation concluded, the biplanes land aboard the flying boat. It's time for the expedition to return to civilization and share their shocking discoveries about the existence of prehistoric life. However, a flock of pterosaurs collides with the flying boat, killing everyone on board. The disappearances will remain an enigma. The expedition has become another victim of this region - the Bermuda Triangle.