The Barunba team was in the same development room at Naxat as him. 
The outsourced programmer on Spriggan Powered sat next to him. It was not someone from Compile. (Ed: It was probably Yagi.) The game was planned in-house at Naxat. 
Some interesting information on Naxat, mostly from programmer Yoshiharu Takaoka (unless noted):
 "Coryoon is genuine Naxat — the only former Sunsoft person is the designer."
 From @tanin1971: "Actually, when I was looking for a job in the '90s, I called the company and was told that 'we don't do development,' and that's when I found out that they didn't develop internally."
 "I think we were the first to develop as Naxat employees, and then the development members of Eternal City joined us."
 "During the development of [Super Real Mahjong] P4 Custom, I suffered a complicated fracture of my dominant arm, but I refused to have surgery and finished the program by myself, using only my left hand to meet the deadline. I couldn't even lie down to sleep, but I got through it mostly by going back and forth between the company's nap room and the development room."
-  "2-3 Custom was by in-house subcontractors (Barunba team), and I was able to advise them on the animation program structure."
-  "At that time, Naxat had two in-house outsourcing teams."
 "Strictly speaking, Eternal City was absorbed by another company (a private company), so it was still an outsourced work at that time."
(Is Takaoka saying Eternal City was done by an outside company?)
 "This was the work of the former Flight-Plan team: W Ring, 1943 Kai, Coryoon. Alzadick, Kaze Kiri, and Eternal City were by the Eternal City team. PC Denjin was the joint work of both teams and Red."
 "The development members of Eternal City were also in the same development room (as Coryoon)."
 Coryoon's voice was Oguro from Kaga Electronics.
 "It was once revealed on some site that Planet Joker was the work of technical students, but that was a lie. It was a game created by a middle-aged team called IMP, who came to Naxat from the Kansai region with a lot of fanfare, claiming they would sell a million copies! The original development team was so discouraged by the game that they all resigned."
(I assume Takaoka is referring to his team in Tokyo. PS Fighting Network Rings was their last game [see hidden message further down the page].)
 "I'm serious! Before IMP arrived, several founding members of Naxat left and established Eighting, so Naxat's internal development collapsed after two departures."
Interesting tidbit hidden in the program data for PS1 Fighting Network Rings. Right near the top of file "SLPS_006.31" there's this message:
- ファイティングネットワーク ＲＩＮＧＳ 最後の社内開発作品で～す
- ファイティングネットワーク ＲＩＮＧＳ さよならナグザット．．．
Ignoring the game's title here, this translates as "The final internal development. Farewell, Naxat..." This might be a message from a staff member leaving the company, but seems more likely a message that the studio was closed after this game's completion. --Dimitri (talk) 01:31, 9 December 2018 (UTC)
I've got a sneaking suspicion the "Tokyo?" team here was actually based in Nagoya. The "Team Nagoyan" staff on Fighting Network Rings looks like a bunch of the same people, plus Flight-Plan was based in Gifu while Mechanic Arms was based in Osaka -- Nagoya is right next to Gifu and not far from Osaka. --Dimitri (talk) 23:47, 11 August 2017 (CEST)
- I don't know. Kyuukyoku Tiger II Plus says Tokyo. Kazuhiko Inoue from Mechanic Arms is on it. The bit about Planet Joker here talks about Osaka development and Tokyo head office development. CRV (talk) 01:03, 12 August 2017 (CEST)
- Hmm, I wonder if it was split into two groups at some point then. Kazuhiko Inoue, Toshiharu Tagami and the other people who went to Mechanic Arms in 1997 (their development was in Tokyo, now that I investigate further) don't really seem to have any crossover with the "Nagoyan" team (Takaoka, Morishima etc) after 1995 or so, at least in the credits I've seen, when they were clearly one unified team before that on the PCE and SFC games they worked on.
- As an aside, the Saturn Tetsuman Special credits list Inoue and Tagami as the Naxat-side dev staff, and also has a special thanks to Naxat IMP. I'll try to get these transcribed over the weekend. --Dimitri (talk) 02:07, 12 August 2017 (CEST)
The title of only Naxat seems to be this.