OK, we were not sure about this place at all. We decided to check it out after visiting Bear Country USA.
It is a fun place, not something I would feel the need to visit every time when I am in South Dakota, one visit is probably enough.
There are steep paths to the place and it can be a bit strenuous because of the mystery forces at work, but it is a short walk.
Upon entering there are some very interesting trees that are growing "down". That really made my son think.
Kids will definitely enjoy this place. My son was laughing because no one could stand up straight and walking was hard. My son liked the water going "up" hill the best. He was amazed. All the kids I saw there were in awe of the place, the adults looks less impressed but it was still fun.
The tour guides really try to involve the kids in the experiments. My son was asked to do two different experiments.
The only thing I didn't really care for about the tour guides is they seem to rush through the ‘tour'. Maybe that don't want you to think too long how things work and what the mystery force is, I don't know, but they do seem a little rushed.
All in all though it is a fun place. The thing I like is kids are still free! You can't find many places that kids are free.
One small warning though, if you are prone to motion sickness this place might affect your stomach a little too much.