Pictures were taken about 18 months after the pour.

Had it rained recently? Does it look like that when it's perfectly dry? It is odd...

The pictures are taken when dry.

Re the pour:

No rain, dry for weeks (Southern California). The only water on the pour was done by contractor the day before the pour.

The job (front & backyard) was done using 2 cement trucks. Both front and back were being done concurrently. After couple hours of pouring and finishing there was a mad scramble and I was told they were running out of concrete.

Finishing proceeded in both front and back for another hour or so. There was only an area of maybe 30 square ft left undone.

Within a day or two the undone area was poured and finished This area turned out fine, while everything from the initial pour became the blotchy mess that the contractor said would dry out and look fine.

Like a dope, I believed the contractor.

"contractor said would dry out and look fine"

That was to give them time to get out of town. Sorry, that does not look good. I'd be mad too.

You could take the contractor to court but, whether you do or not, You will either have to replace the concrete or covert it with another decorative topping. I'd talk to a landscape person re options. Be sure to post a review on that contractor's web site. Just awful.

Our new concrete looks similar. our contractor said that it will look like that while it cures. does anyone think a pressure washing may help?

That look's like more than two loads and definatly more labor than average for the square surface feet. The appearance can be changed relitavy inexpensive compared to repouring but the larger problem is possible failure in the form of spalling or cracking and no telling what else. It look's wet but difference in distrubution of portland caused uneven colors. You've probably waited to long to do anything with contractor but you can check your state's limitations to see if you can still get under the wire. What are you looking for from us?