Hong Kong has two major themeparks. Ocean park and Disneyland. I am going to introduce both of them to you!
Ocean Park is a theme park based on sea animals and rides, that's why it's called Ocean Park! However, none of the rides are interpreted with sea animals. There are many rides, including the cable car, Hair Raiser(roller coaster), carnival games, etc. The rides in the Ocean Park are more for teenagers than youngsters. It is Ocean Park, so there must be animal exhibits. Many of them give you useful facts on each animal. Plus, people there vary from ages 9 to 99, so it's basically for everyone. Like every theme park, there are some new rides once in awhile. Everything there is very exciting, especially at Halloween! Every staff member's makeup is so scary! It would totally freak you out! It is very profitable because you have a better experience in what "fun" means and it's pretty cheap, $280 for an adult and $140 for children. A great idea if you're traveling to Hong Kong.
Disneyland is more for immature children because everything is based on Disney characters, probably for ages 2-8. There are only new rides for about every 2 years, so pretty much everything stays the same. Many children would probably consider it heaven for them because they make it like a very big castle. There are parades during the day and fireworks at night. Halloween is absolutely not scary there, so very good for children. It is a bit more expensive than Ocean Park, $399 for adults and $285 for children. If you've been to the Disneyland in America, this Disneyland would seem much smaller with fewer rides.
If it were me, I would choose Ocean Park because of my age. For my parents, maybe they would prefer Disneyland more because it's very child-friendly. Either way, come visit Hong Kong and don't forget to visit both parks!