EDIT: did you also know he worked on a game called "Glitch". the game didnt really go anywhere, but it worked out thanks to the team creating a little communication tool called "Slack".
Slack still has little callbacks to Glitch. Slack was based on Glitch's infrastructure. You can set your Slack notification sound to 'Hummus', which I assume was a sound bite that would play whenever you made hummus in Glitch.
Glitch was a lot better than you might imagine from first glance. It got that playfulness, without being simplisticly childish, that you might recognize in Keita's other work.
Glitch made the forced error of being designed and implemented in the tail end of the era where Flash was the obvious choice for a web based game. They considered switching to other technologies once it became clear Flash was a dead end, but there really was no good alternative.
They released all their assets in the public domain (CC0)! This includes their clientside Actionscript code.
glitch was the best mmo ever because it rewarded prosocial behavior, like mining with friends got you more ore than doing it alone, you got early game quests to seek out fresh noobs and give them stuff, and the halloween event had achievements for giving away candy
