Start and finish are at the same location, so no net difference. My watch measured about 120m elevation. First 5k is mostly climbing, second 5k is a bit hilly but net not much difference, one final climb from 10 to 11 and then from 11 to the finish is downward. For Dutch standards, the course is really hilly, but I expect for American standards it would not be that special.
https://www.nnzevenheuvelenloop.nl/parcours -> the bottom video might help with a bit of information of the course.
Joshua Cheptegei ran a world best here in 2018 and the previous world best was also set on this course, so I suppose it's a fast course.
This is good information thank you. How is the net elevation 120m if the start and finish are in the same place?
Something about the course must make it fast then.
Obviously the downhill finish can lead to very fast times as long as you put in a big effort over the first 5k.