Holy SMOKES, I think we might have a winner in our unofficial & just announced "Ugliest Roof Of The Year" category.
First, the valley is in short sections. Looks to me like they used up old or leftover pieces of flashing from some other job. You might take a coathanger & make a small hook in one end, then stuff it up under the shingles along the valley & see just how wide the valley metal is (may be easier to peek in there @ the bottom of the valley, but I don't want you to break some seal or remove any nails).
You REALLY REALLY want w valley in there. That way, any water flowing down the slope (not the valley, the slope) won't wash up under the other side of the valley metal.
Think of it like a kid on a skateboard who is doing the 1/2 pipe... if there was a small wall in the center, he's not going up the other side, is he?*
Now, granted... that's a fairly low slope; maybe a 5:12 from what I can see. Do us a favor & back off a bit; take a photo of the house from the street & all the way from the back fence so we can get a better idea of how the house as a whole looks.
Additionally, this pic here...
That has GOT to be the sloppiest valey termination I think I've ever seen in my life. Now, there is every possibility that your "roofers" (can anyone say "day labor"?) will say they've cut it short so that water will not overrun the gutters - but then you really need backsplashes. Problem is, it appears your gutters might sit too low for a backsplash to be of any decent use.
On that hip there - what's up with the hump about 1/2 way up the run? Is that a bit of an architectural change in the pitch or just bad decking?
I'm also in the camp of wanting to know what is going on with the ridge vent.
[John Wayne]That's some mighty tall ridge vent you've got there, Mister...[/John Wayne] & it doesn't look to me like you've got Z Ridge or any other type of "high profile" ridge cap (much less a need for a steep slope ridge cap shingle).
You've done well with the photos, we just need to refine the shots a bit more.
I'll do a sketch for how the valley metal should extend off if anyone wants to give me some specific measurements...
*Note: Skateboarding is not a crime.