Just so everyone knows, $19.99 is the new MSRP for all these games. Every Best Buy should have 2 cardboard display stands full of these if not more. $14.99 is still a nice $5 off though.
I do know that I've been waiting for Twisted Metal for quite some time. For the longest time it refused to go below $29.99. $14.99 might be the best "readily available" deal so far on Twisted Metal.
Sly and God of War: Origins have definitely been this low before (maybe even as far back as 2 Christmas's ago). But I thought those games were actually getting sort of hard to find at one point? (GoW: Origins replaced by the full GoW collection). If there's a new display it's probably a reprint of all of these.