Had family fun, but lots of hidden costs.
Entry was expensive and then you can't even use any of the water slides without an additional wrist band for 2,800 yen per adult. Floats for the kids cost extra and the food was (as expected) overpriced and good to fair in quality. The Lazy River Ride, 40 deg Onsen (small and crowded but able to grab some space), and the Polynesian Show were highlights as well as being able to enjoy swimming in the enclosed Hawaiian themed dome in the middle of -4 deg weather. Plenty of options for public transportation/busing  and parking all day was only 1000 yen.