He's setting up his own indie studio and will make the types of games he used to make. It would be cool if he had some original ideas, but its not like the world is overflowing with quality Metroidvania games (though there are a few out there).
Today, Koji "IGA" Igarashi has announced that he is forming his own independent development studio and is hinting that he will make a game in the vein of his most popular works.
In a statement released to the press, he has revealed that his last day with longtime employer Konami was March 15. He is in the process of creating a "small" studio.