With Sonic 4 they had to pay a whole team to make new graphics, music, sounds, and to design levels. With Sonic CD, they only had to pay Taxman, who had already done a lot of the work before Sega hired him to officially port the game. That's what I think anyway. But yeah, I'm surprised they didn't knock the price up a bit more since it deserves a higher price more than the emulated "ports". Heck, I think I got it for $1.99 on iPhone.