If people are keen, I can confirm that Sonic Generations can be bought easily enough on Amazon and registered on Steam without a VPN. Buy it using your regular credit card using a US account, but when entering the address I just entered as close as I could (there was no country for old options) and for the state I just used CA and postcode was 90210. I forgot I saved the details from it earlier (not thinking it would work) and I accidentally the whole thing when I revisited.