SA2 and Heroes and Shadow were made for the American market.

>Sonic Team USA's development is based in America, but how did that come to pass?
Iizuka: The first Sonic game was made in Japan, but the characters were originally made to target the American market, which was the largest market then. That's why, even back then we had the notion that we should be making these games here, because that would help Sonic absorb more of the American atmosphere. So starting with Sonic 2 we did just that, and have been developing Sonic here in the US for awhile now.