LocoRoco

LocoRoco is divided into 5 worlds each consisting of 8 levels. In each level, the goal is to reach the end point of the level, with the player scored on the number of LocoRoco found, the time to complete the level, and other factors. There are six varieties of LocoRoco in the game, identified by their color, appearance, and musical voice, but outside of the first "Yellow" one, the rest are unlocked as the player completes the level. The player can then opt which LocoRoco they want to use for a level, however, this selection has no fundamental gameplay effects and only changes the songs used.

LocoRoco act as blobs of gelatin, deforming from their normally round shape when demanded by the environment. Certain beings in the world can change the default shape of the LocoRoco into other forms, such as squares or triangles, which lasts until the end of the level or they encounter another similar being.

Living peacefully on a faraway planet, the LocoRoco and their friends, the Mui Mui, help grow vegetation and look after nature, making the planet a pleasant place to be, playing and singing the days away. When the Moja Troop comes to the planet to take it over, the LocoRoco do not know how to fight against these invaders from outer space. As such, the player assumes the role of "the planet" that is capable of guiding the LocoRoco around to defeat the Moja Troop and rescue the remaining LocoRoco, returning the planet to its peaceful ways.

LocoRoco was envisioned by Tsutomu Kouno, who had previously worked on the development of Ico. While on a train during the second quarter of 2004, Kouno had used a PDA to sketch a game that would involve multiple similar characters that would not be in direct control of the player. He realized the planet-tilting aspect after seeing how rotating the phone with the sketch around would lead to a compelling game. At that time, the PlayStation Portable was nearing release, and Kouno felt the unit's shoulder buttons would be appropriate for the tilting controls.

Kouno also opted to develop for the PSP to break the mold of other, more complicated sequels from PlayStation 2 games that were being developed for the unit and instead create something that "really seemed at home on the PSP". Kouno also wanted "every aspect of the game [...] to be unique", and led to his choices for graphics and music in the game.

LocoRoco has received mostly positive reviews from critics. The game was consistently praised for its bright and bold graphics. Charles Herold of the New York Times compared the graphics to Katamari Damacy, calling them "simple" and "pretty" while Sam Kennedy of 1UP considered it akin to "playing out an adorable cartoon". The unique environments of each level were also credited to help the game's charm, with Kristan Reed of Eurogamer believing that the game presents a "look and feel unlike anything we've seen before" and that shows "a truly brilliant realisation of how to take 2D gaming into uncharted territory."

The music of the game was considered to be "quirky and catchy", with Will Tuttle of GameSpy saying that "there's a good chance that you'll be humming some of the tunes all day". The game, at times, was compared to a "slow-motion version of Sonic the Hedgehog" with the player controlling the LocoRoco as they move up and down hills and through loop-de-loops in the level. This gameplay allows the game to be easily accessible to players, with IGN's Juan Castro noting that the controls are "not simplistic so much as it's refreshingly elegant", and Kennedy commenting that while LocoRoco is not perfect, it was "perfect for the PSP". As noted by Neil McGreevy of the BBC, LocoRoco "is the best game Nintendo never made."