I took my 3 1/2 year old daughter to see this movie and she absolutely loved it! Wants to go see it a second time.
Interesting reviews from critics though. Storyline lacks, etc. I wonder if Wonderpark was made for middle-upper aged adults and if so, I would agree. But I'm pretty sure the intended audience is children. I could be wrong though. There should be a review service where the critics are comprised o the intended audience demographics.
At the end of the day, kids seemed to love it and kids ask their parents to go to the movies. Seems like it hit its mark to me.