Is it normal to find cracks in new concrete?
Concrete will crack naturally on its own unless it is given a place to crack such as control joint or expansion joint. As the concrete is curing it is heating up and expanding.  In the summer time, I have seen the slab crack before being able to walk on it.  

Regarding footprints, it is tacky. However, the roughness can actually help the concrete and thinset to bind unless it is flaking.

One criticism......the young lady wearing the flip flops should not be walking around a construction site. Stepping on nails, rusty re-bar, broken glass etc is a distinct possibility.  Safety first! 

As suggested by another responder, if you feel excessive water has been used then a core sample can be done and a test break can ascertain whether the concrete is no good.