Why is the Pokémon Pinball cartridge so thick?

Pokémon Pinball, released in Japan in April 1999 and in North America on June 28, 1999, is built around a pinball table with a catching mechanic, and its signature feature is physical: the cartridge itself rumbles as the ball strikes bumpers and Pokémon. To do that it carries a motor the standard Game Boy cartridge shell could never hold.

So Jupiter, the developer, built a bigger one. The Pinball cartridge is visibly swollen, with a battery compartment for a single AAA battery that powers the rumble independently of the Game Boy's own batteries. It is one of a tiny family of Game Boy cartridges with moving parts, closer to a toy than a ROM.

The object rewards a collector's attention. The battery door, the deeper shell and the weight in the hand are all original features, not damage or a bootleg shell, and a copy with a corroded AAA still inside is a copy whose previous owner never read the compartment.

Pinball was also a first in a quieter way: it brought the Pokédex structure to a spin-off, asking players to catch 151 Pokémon across its two tables, the Red Field and the Blue Field.