Actually got to this place last month, although its name changed to Splash City for its second season. Went there on its last day, and the place was packed. It's located in part of the parking lot for Belmont Raceway. All of the bitumen has been covered by astroturf or plastic mesh, which isn't too harsh on the feet. The food was reasonable, although there was about a ten minute wait. There were plenty of tables under cover, so you didn't get too burnt.
It was very much a family and/or tweener crowd as the only ride for adults and big kids were the taller slides. There was also an inflatable maze, obstacle course, kids playground and main pool. The seven storey slides are scary because the whole tower wobbles in the breeze. The ride down is fast (50kph), but over in seconds, and is not too much of a bother. The three storey slide was probably more fun, because you had to climb up the ladder at the back too.
There is a great view of Burswood from the park, especially of the new stadium. I'm sure Splash City will be on again next season. It would be nice if they made some of the rides a little more permanent.