That's a good point and I also wonder if the US version has different end credits...
I've never finished Afterburner II and Outrun, maybe I can add them to my to-do list (as well as Thunder Blade). However, both games have 'reprogrammed by NEC Avenue' mentioned on their front cover though, so I have the feeling they were programmed by NEC avenue, but who knows...
Just found out Afterburner II was done by Bits Laboratory.
They also did Fantasy Zone, both the Altered Beast releases, and Gain Ground SX. I guess they liked doing SEGA ports.
Among the other, non-SEGA ports they did on the system: all 3 original Darius games (not Darius 2), Toilet Kids, Veigues Tactical Gladiator, Hellfire S, Hi-Leg Fantasy, Bubble Bobble 2: Rainbow Islands, Sidearms Special, Space Invaders CD, CD Mahjong, and Splash Lake.
Games they cooperated on: Download, Son Son II, Ai Cho Aniki, and some quiz and gambling games.