Wurm Journey to The Center of The Earth

An oft-overlooked little gem from the height of the NES's popularity, WURM details the exploits of a team of explorers sent to investigate the source of mysterious tectonic activity (not to mention the fate of four previous expeditions that have gone missing). They travel in a tunneling vehicle called the VZR, nicknamed the "WURM" by the manual.

As the team ventures deeper underground they find their predecessors were ambushed by monstrous members of the Nonmalta empire which is fighting the beleaguered kingdom of Dinamur for control of the underworld.

WURM provides examples of:

 * Aerith and Bob: We've got characters like Dan, Allan and Sylvia alongside Moby (a female character), Locke and Ziggy.
 * Beauty Equals Goodness: The "good" subterranean empire, Dinamur, has human-like inhabitants (assuming the royal family is any indication), while the evil empire, Nonmalta, is made up of hideous monsters.
 * Beneath the Earth: The whole game.
 * Drill Tank: The VZR.
 * Everything's Better With Princesses: One of your advisors is the princess of the underground kingdom (after being rescued from the bad guys, of course).
 * Jigsaw Puzzle Plot: The story of the various underground civilizations is revealed a bit at a time, but it's easy to get lost unless you're paying really close attention.
 * Kick the Dog:
 * Power Source: One of the game's more annoying aspects is that while the VZR automatically repairs damage, if the player doesn't find a steady supply of randomly-appearing fuel crystals they die.
 * Send in The Search Team
 * Transforming Mecha: The VZR can change into a hovercraft or a plane. Although for some reason you need to salvage parts from one of the other VZR's before it can change to plane mode.