I can't complain about my own article not getting reviewed while I haven't the others, so here you go.
Obviously, references. There's a "citation needed" tag, and a few paragraphs do not end with citations.
Credits should be listed chronologically, not reverse-chrono.
Biography needs to be better-organized. Ideally, it would be divided into at least two subsections, but even if not, the information should be presented chronologically (for example, why is the info about his education after that of his entire career so far?).
Is any more information about Iris or his software-engineering career available? Paragraphs this short are discouraged.
The lead needs to be rewritten to summarize the article better, and most importantly expanded. It doesn't list any of the games he's worked on or his pre-game history, for instance.
Is his last name really "Sega"? (What nationality is that?) Might want to include a note somewhere that it's not related to the game company's name.
Can you find reliably sourced information about his musical style?
Nothing egregiously stands out about sources - MySpace, LinkedIn, and the normally unreliable publications raise eyebrows, but they're all being used as first-party sources so that's fine.