ChuChu Rocket!

ChuChu Rocket! is a 1999 action puzzle game developed by Sonic Team and published by Sega for the Dreamcast. The objective is for the player to place arrows on a board to lead mice into escape rockets while avoiding cats. The game features single-player modes in which a player must save all the mice on a board, and a multiplayer mode in which players battle to collect the most mice.

Directed and produced by Yuji Naka, ChuChu Rocket! was developed to test the Dreamcast's processing power by displaying many characters at once, and also to test the online functionality of the Dreamcast and Sega's servers, as it was the first Dreamcast game designed to make use of online. The knowledge gained from the network portion of the project helped Sonic Team in their development of Phantasy Star Online (2000). When it arrived in the United States, Sega held an online tournament where players could battle against Sega and Sonic Team employees. In PAL regions, it was given free to subscribers of Sega's online gaming service Dreamarena. Although Sega's online services have long shut down, the game can still be played online via private servers.

ChuChu Rocket! was a commercial and critical success. Critics praised the chaotic and addictive multiplayer and the simple and cute Japanese aesthetic. Sega's network gaming service received some criticism for lag. ChuChu Rocket! was ported to the Game Boy Advance in 2001 as a launch game, and gathered interest as the first game published by Sega for Nintendo hardware. It was later ported to iOS and Android; both of these versions were delisted from their storefronts in 2015.

ChuChu Rocket! is an action puzzle game. The basic rules of the game require the player to guide mice, dubbed "ChuChus", into a rocket while evading them from dangerous cats, dubbed "KapuKapus". A brief premise is provided in the instruction manual, explaining that ChuChus are living on a space port that is invaded by KapuKapus one day. In their frantic state, the ChuChus begin running around in chaos, and so the player must guide them to their rockets to save them. Both ChuChus and KapuKapus run in a straight line, and turn right when they hit walls. A player can place up, down, left, and right arrows on the field of play, redirecting characters that step on them. Up to three arrows can be placed by a player at any time; placing a fourth arrow will make the player's oldest arrow vanish, and all arrows fade away over time. If a KapuKapu hits an arrow twice, the arrow disappears.

There are several modes of play within ChuChu Rocket! including a single-player puzzle mode, a puzzle editing mode, a cooperative challenge mode, and competitive multiplayer modes. In the puzzle mode, the player is provided a limited set of arrows to place on the field to save all the ChuChus in play. The puzzle editing mode allows players to create their own puzzles like this. In the challenge mode, players are given 30 seconds to save the ChuChus in play without any arrow limitations as in puzzle mode. In the competition modes, each player has a rocket and must guide as many ChuChus as possible into their rocket in the time limit. This mode supports up to four players, either in free-for-all or team-based fashion.

ChuChu Rocket! is notable for being the first Dreamcast online multiplayer game. During the time Sega was operating its servers, players were able to play the competitive modes online, while also being able to upload their custom puzzles and download those made by other users. Players could use an onscreen or physical keyboard to chat with other players. Servers for the game's online functionality were brought back online by fans in 2016.

ChuChu Rocket! was developed by Sonic Team. Director and producer Yuji Naka conceived the game as a way to use the power of the Dreamcast to create 100 sprites moving at once. He believed there are two trends to use evolving hardware: one is to make increasingly beautiful graphics, while the other is to squeeze as much processing power to use it to its fullest; he chose the latter in this case. Naka and his team found difficulty working on the networking component, but believed it was a good learning experience. Part of ChuChu Rocket!'s purpose was to test the capabilities of online multiplayer gaming on the Dreamcast; the team used what they learned to help drive the development of Phantasy Star Online (2000). A NAOMI arcade version of the game was also planned, but later scrapped.

Sega announced ChuChu Rocket! on September 2, 1999 as Sonic Team's second game for the Dreamcast after Sonic Adventure (1998). Prior to the game's release in Japan in November 1999, Sega promoted the game with a website dedicated to ChuChu Rocket!, and a 15-second commercial advertising the game was solicited to television stations across the country, with the commercial also made available to download through the website. ChuChu Rocket! released in Japan on November 11, 1999 and climbed to the top of the Japanese sales charts in its first week on sale, selling 35,000 copies and knocking the PlayStation release of Chrono Trigger off the top spot. That December, video game magazine Famitsu held a contest using a ChuChu-themed minigame for the Dreamcast Visual Memory Unit (VMU) that could be downloaded from the internet. Players who completed the minigame were given a password to send to Famitsu. Various prizes were given out to winners of the contest, including Dreamcast controllers, VMU stickers, and pens.