Looks like this Sonic CD port uses the Retro Engine from the Sonic Retro user "The Taxman", looks like he's helping SEGA with this port. Here's some info about this port: The quotes were taken from this topic in Sonic Retro, from page 11 and beyond: http://forums.sonicretro.org/index.php?showtopic=26192&st=150
^^ I do find it funny that Sonic Retro is allowed to flourish, and yet the Streets of Rage remake was forced to shut down [After they released though, so its on the internet for good ]