ChuChu Rocket!

(Image courtesy of Retrothing)

ChuChu Rocket! was originally released for the Sega Dreamcast by Sega (with the game being developed by Sonic Team), and it has since been released for the Gameboy Advance and iOS as well. It is a single- and multi-player puzzle game with an unusual and unique form of gameplay, with the player placing arrows upon the playing field to direct mice to safety, while making them avoid the cats that may harm them.

Although it has a very simple idea behind it, ChuChu Rocket! is more complex than one might think. In the single-player puzzle mode, players are challenged to use a limited number of arrows (with pre-set directions) to keep the mice away from cats and lead them into the rocket ships placed on the level. Every mouse constantly walks forward, only changing direction when bumping into an object (in which case it turns around or goes around a corner, depending on the situation) or an arrow (in which case it moves in the direction the arrow points). The puzzles start out easy, but grow very difficult as more cats, walls, pits, and more are added into the mix, especially since the player cannot see how the mice will actually act till they are done placing their arrows. The multi-player mode is more hectic, with the players all placing their arrows (of which only 3 can be placed at a time, with old ones disappearing after a short time or if a 4th one is placed) during live gameplay and trying to drive the mice into their own rockets instead of their opponents. The game's online multi-player became so popular that the game was eventually given away with the Dreamcast in order to increase the console's sales.

The game's concept is, of course, very odd. However, it is also one that could have very easily been prototyped physically, at least for its single-player mode. The mice, as mentioned earlier, follow a simple set of rules and all interaction with the map happens before the mice move, so it is likely that the designers simply used a grid drawn on paper as a prototype of the map, with different paper tiles representing the mice, cats, arrows, pits, and walls. As long as the rules governing mouse and cat movement were followed correctly, they could have been manually moved through the board to see if the player had completed the puzzle correctly.

For the game's multi-player mode, a software prototype was probably required. It would have required too much work for players to manually place arrows while also moving every mouse on the board, so a software prototype could have been set up instead. It would have been focused on making sure the mechanics worked correctly, since if any of the mechanics did not work, the entire mode would be unplayable, either due to the increased difficulty that the mice moving too fast would cause, or the frustration a player would have with the mice if they didn't move as the player directed them to. Prototyping the game must have required carefully making sure everything worked as the designers needed it to, and it seems that they managed to pull it off.