His official website: http://www5.airnet.ne.jp/jokerjun/
His Twitter: https://twitter.com/JokeRJUN
He put a lot of references to previous works in his Btooom! manga. Colonel Longhena appears in it, the lead female has Casper's head, Rosa and Follett also make appearances, and on and on.
His Otogi Matsuri manga is practically a parallel universe to ESP Ra.De.
Cool stuff, thanks for posting it. In the near future I'm going to try to post some discussion topics on Makoto Asada's (ex-CAVE) visual novels released on 5pb in recent years. Psycho Pass and Yu-no, with Mystereet F coming soon. I have the big boxed Yu-no limited edition and it's a glorious package.