Godzilla: Monster of Monsters is a Nintendo Entertainment System video game released in the US in 1989 by Toho Co., Ltd.
The game features two playable characters, Godzilla and Mothra. The player uses both monsters in turn by selecting the desired character on a virtual gameboard, representative of the planet it is on, and moving it like a chess piece. Each space is a hexagon that represents playable, side-scrolling levels.
Each board contains several monsters from the Godzilla series such as Ghidorah, Moguera, and Mechagodzilla, and the objective is to clear each board of enemy monsters before advancing to the next board. Battles are fought when the player moves Godzilla or Mothra adjacent to an enemy monster, and are reminiscent of a versus fighting game. If the player moves to a space that is not adjacent to an enemy monster, the player instead plays a small side-scrolling level.
Source: Wikipedia, "Godzilla: Monster of Monsters", available under the CC-BY-SA License.