The offer is valid on the PlayStation 3 and Xbox 360 versions of both games. DmC is being sold for $59.99, its regular retail price; the price for Resident Evil 6 constitutes a 75 percent discount off the regular price of $39.99.
Best Buy lists the deal as being valid "for a limited time," so if you're interested, we'd suggest you jump on it sooner rather than later.
Resident Evil 6 launched last October to middling reviews. On the other hand, DmC: Devil May Cry — which is due out tomorrow, Jan. 15 — has been well received. Check out our review for more details.