Rodan was planned for a 1991 release on the Nintendo Entertainment System (NES). The game was under development, internally, at Toho. The title was also rumored to be exclusive to the US market, although the legitimacy of this claim is unknown.

In 1990, advertisements for the game began to surface. Toho started packaging a full page promo for their upcoming titles with Godzilla Monster of Monsters (1989). The ad showed off the 1989 Godzilla game for the NES, Circus Caper (1989) for the NES, Godzilla (1990) for the Game Boy, Times of Lore (1990) for the NES [a port of the 1988 Commadore 64 game] and Rodan. The game included the caption:

"A giant flying reptile assaults the earth! Rodan, Godzilla's arch enemy! Now an exciting NEW game!"

For whatever reason, the Rodan portion of the advert dubs the title character as "Godzilla's arch enemy", despite the fact that they had only engaged in combat once at this point in time and had much more frequently been showcased as allies.

Meanwhile, magazines in 1990 started to take notice of Toho's next project for the NES. Nintendo Power's 16th issue made mention of the title in their Game and Watch section. The magazine stated that Rodan was a "sort of sequel to [Toho's] NES Godzilla game." Gamepro, in their September issue, also made mention of Rodan by citing the title as "a sequel to Godzilla [Monster of Monsters]."

A short while later, the game was swept into obscurity only to resurface in 1991 as Godzilla 2: War of the Monsters, according to Nintendo Power. Exactly how much was changed when the title took a new name is not entirely known; however, the game shares very little in common with Godzilla Monster of Monsters (1989), beyond the cast of monsters. Reportedly, though, the reason for the change in direction was that Toho felt the Rodan name wouldn't sell as well as another Godzilla game.