In the year 1999, the world is suddenly facing intensive natural disasters. Scientists are perplexed and decide that research on the inside of the earth is needed. To this end, an underground vehicle is constructed to explore the underworld. They call it the VZR, but the crew know it more commonly as a Wurm. Four different Wurms have already been dispatched and mysteriously disappeared, so a fifth Wurm vehicle is ready to launch crewed by the best and the brightest. Crew Chief Moby has been chosen to lead the mission, even though she has lost both her love and father on previous Wurm missions. It will be up to her and the crew to figure out this mystery and rescue the other Wurm members. There's also a matter of mysterious crystals that have been found underground...
Wurm: Journey to the Center of the Earth is a game featuring multiple sequences. The player controls the VZR vehicle, and occasionally Captain Moby when she ventures out on foot in vertically and horizontally scrolling sequences as well as a first person battle against enemy monsters. Players progress through 5 levels, in which the VZR-5 investigates the fate of the other VZRs. After the completion of each level, the player gains a crystal, which will unlock additional weapons for the VZR, mentioned below.
The VZR is controlled in both a side-scrolling sequence and a top-down vertically scrolling sequence. In the side-scrolling section, the VZR is able to change between Tank Mode and Hover Modes mode. In the top-view section, the VZR is able to change between Hover Mode and Aerial Mode. The Tank mode drives along the ground, firing in three directions and uses a drill to tear down obstacles. The Hover Mode can fly around the screen, but uses fuel constantly while doing so. Like the tank mode, It can also fire in three directions and has the drill, however the weapon can be changed to two power-ups: energy balls that fly across the screen and a wave weapon the shoots out in both directions. The Aerial Mode is a fighter jet form and sacrifices the obstacle-clearing drill for a laser weapon which bounces off of walls. In all forms, the VZR has a Life bar and a fuel bar, either of which will end the game if it runs out (though Tank mode does not use the fuel). Defeated enemies will sometimes drop fuel restore power-ups.
The VZR also engages enemy monsters in a first person shooter game. The player moves the perspective of the VZR left and right, and is able to fire the weapon. There is a "Possibility" percentage on the screen that determines when the player is able to kill the enemy creature. This possibility must reach 100% before the battle is over. In order to raise this possibility, the player can attack the monster's weak point... slowly driving it up, or the player can "talk" to crewmates on the VZR who will analyze the monster with sensors and move the the Possibility value up (or down). Players can also change between different weapons, some of which are more effective than others, all of which are fired the same way on the screen.
When Captain Moby leaves the VZR vehicle, the action changes to a side-scrolling platform game. Moby must navigate her way through a maze of different rooms, looking for the objects or persons required for her to open different locked doors. Moby's only abilities are a jump, a karate kick and a pistol. Moby has an ammo bar which determines how many times she can use her pistol, and a life bar, which ends the game if it runs out.