In Agharta: The Hollow Earth, set in 1926, the player takes the role of a nameless pilot who gets hired to find a famous scientist who disappeared during an expedition to the North Pole. But after a crash he finds himself in a mysterious underworld, the hollow earth. Here he has to stop a villain who wants to destroy the world...
The player indirectly controls his character with a traditional point & click interface. He explores his environment, collects everything he finds and solves inventory based puzzles. He also meets various enemies which he fights by throwing rocks at them. These rocks are infinite. Sometimes the player can also use items to avoid enemies, e.g. a tin of tomato soup as distraction.
Another game element is the pilot's dog: the player can call him and give him simple orders, e.g. to fetch something.
The mouse cursor doesn't change its form over interactive elements and there is no manual saving: the game automatically saves.