Colorado St been able to execute on virtually all of the weaknesses CU has shown in the last two games. CU's OL is small and fairly slow, Edwards is a scat back and they ain't got no other running game to speak of, basically all of their DBs outside of Hunter are not good, I honestly didn't know if someone could attack all of those aspects at once with how weird the Pac 12 is.
CU has been much better at adjusting to the pass on D, vs. the run. So they may be fine in the end.
edit: forgot to mention their tendency to do the gimmicky west coast style passing early in games. They lulled TCU and Nebraska to sleep with that.