Capcom unveiled the Devil May Cry HD Collection in December 2017, bringing an updated collection of DMC 1, 2, and 3 (but not 4 or the DmC reboot) to PC in March. Twitch Prime members will have the opportunity to grab the original DMC sooner than that, however, and more importantly, for free.
The free DMC will be available on February 27, two weeks in advance of the Devil May Cry HD Collection. Just log into your account, head to the relevant Twitch patch, and stake your claim. If you like, the full DMC bundle will be available for purchase through the Twitch app too, but you'll have to wait for it to go live first.
Twitch Prime offers ad-free viewing on Twitch, exclusive emotes and a chat badge, discounts on games sold through Amazon, and various gaming-related freebies—like this one, for instance. It's included with Amazon Prime, and while it may not be worth the $100/year price of admission on its own (Samuel recently opined that it is not), it's definitely a nice plus. And if you happen to have Amazon Prime already and didn't know about this Twitch business, there you go.