Early life Koizumi was born in
Mishima, Shizuoka on April 29, 1968. He played his first video game,
Super Mario Bros. 2, at the age of 21 when he borrowed a friend's
Family Computer console. A graduate from the Visual Concept Planning Department of
Osaka University of Arts, Koizumi studied
film,
drama,
animation and, to a lesser extent,
storyboarding. He had originally intended to become a
film director but applied at
Nintendo instead to pursue his goal of creating a kind of drama only experienced in video games. The company's close proximity to his university also played a role in his career choice. Koizumi later experimented with a polygonal, side-scrolling remake of
Zelda II: The Adventure of Link. Developed for the Super Nintendo Entertainment System, the prototype was based on
chanbara action, a type of Japanese sword fighting. With
Super Mario 64, Koizumi became assistant director and animated the 3D models, among others working on Mario's swimming movements in cooperation with director
Shigeru Miyamoto. While developing
Super Mario 64, Nintendo's employees devised rough concepts of a three-dimensional
The Legend of Zelda game with a bigger focus on puzzles and less pronounced action elements. Koizumi wrote several notes on sword battles and combat with multiple opponents. When he joined Toru Osawa and Jin Ikeda, he was the third staff member to work on the game that would become
The Legend of Zelda: Ocarina of Time. Koizumi consulted his earlier notes and tried to inject leftover ideas from
Super Mario 64 into this new
Zelda installment. Koizumi replaced the simple triangle the team had implemented to mark the player's focus with a fairy that would change colors based on the friendly or hostile nature of the Z target. Furthermore, he was in charge of the
player character Link and designed other characters such as the horse Epona. He also worked on the 3D environments, the camera system, the
items and some of the event design, such as the scenes where the player overhears the conversations of other characters. Following
Ocarina of Time, Koizumi was designing a "
cops and robbers"-style board game that had the player catch a criminal over the course of a week in-game, or roughly equivalent to an hour in real time. However, he was pulled off the project and asked to help develop the sequel to
Ocarina of Time, ''
The Legend of Zelda: Majora's Mask''. Koizumi carried over his "cops and robbers" idea with the time limit and expanded it into a world threatened by a falling moon after he had daydreamed about such a scenario. The concept was corroborated by Miyamoto's wish to have a "compact"
Zelda that could be played over and over again, and the ideas eventually evolved into a system with a three-day
time loop. Koizumi was again placed in charge of the game's player characters. The game's side-scrolling nature sprang from Koizumi's attempt to overcome problems with complex camera controls in 3D titles. These efforts continued in his next title,
Super Mario Galaxy. The game's spherical levels eliminated the possibility of the player getting lost or the need for adjusting the camera when reaching the end of a flat surface. Koizumi directed
Super Mario Galaxy and was heavily involved in the creation of its story, deciding on the inclusion of the optional fairytale book that tells the characters' backstory. Koizumi also served as General Producer of Nintendo's 2017 video game console, the
Nintendo Switch. He alongside Shinya Takahashi also succeeded
Satoru Iwata as the host of the
Nintendo Direct video presentations since 2017, and has been doing so since the live streamed Nintendo Switch Presentation, which took place on January 12, 2017. Koizumi was part of the board of directors of Nintendo's subsidiary
1-UP Studio as one of its representative directors from 2013 to 2023. In October 2022, he joined the board of directors of
Nintendo Pictures. In 2023, Koizumi was promoted from Deputy General Manager to Senior General Manager at
Nintendo EPD division after almost 10 years in the position, below only Executive General Manager Shinya Takahashi who also was promoted at the same time. ==Game design==