PC users are getting a triple-dose of Sonic today, as Sega is bringing two games and a piece of DLC to the platform all at once. It might seem like these are just suddenly popping up on you out of no where, but it's Sonic, and that's kind of what he does.
Both Sonic CD and Sonic the Hedgehog 4: Episode 1 are available for the first time on Steam. The service is also hosting a Sonic sale so you can speed it up on the cheap. Plus, you can grab the Casino Night Pinball Stage for Sonic Generations.
If you have to choose, Sonic CD is one of the most critically acclaimed Sonic games to date, and cheaper than the others to boot. Check out the video below to see the Spiral Knights incarnation of Metal Sonic.