I hate to say this, in 28 years of working construction I have never seen a slab prepped like yours.
What is under the poly?
It may be deceiving but it looks like a lot of the rebar is laying on the poly.
There should be two #5's min. in the thickened edges, rebar should have a min. 3' clearance from the dirt.
If you streach a string line from side to side, what do you have for concrete depth?