All the Sonics, PC – £15.59
All the Sonics, PC – £15.59
Includes:
Sonic the Hedgehog,
Sonic the Hedgehog 2,
Sonic 3 & Knuckles,
Sonic Spinball,
Sonic CD,
Sonic 3D Blast,
Sonic Adventure DX,
Sonic The Hedgehog 4 Episode 1,
Sonic The Hedgehog 4 Episode 2,
Sonic Generations &
Sonic & Sega All-Stars Racing.
To purchase digital games from Amazon US, use your UK Amazon account, and add a US billing address to your account. This address needs to be a valid US address, but nothing will be sent there, and you can access all your games through their website. Some card issuers may charge a fee.

They all activate on steam now.
Source: http://www.amazon.com/dp/B00AG21KGU?tag=s9albw-20
Its seems they added new pages rather then editing the existing ones
FYI, It’s not ALL the Sonics, it’s missing the recent re-release of Sonic Adventure 2.