Waterpark Aquabrava is the main family waterpark for Roses, with slides, pools, and hot-weather entertainment aimed squarely at summer visitors. It is commercial and seasonal, but in a beach resort that is part of the point: families often need a break from sand, sun, and restaurant terraces.
Go with the right expectations. This is not cultural sightseeing, and it is not trying to be. It is a practical, high-energy day out for children and teenagers, especially when the tramuntana is up or everyone has had enough of the beach.