Citistore is at Metro City Phase 2 in Polam, Tseung Kwan O. The kids section is on the 2nd level. I was in there today and came across the Ocean wonders.
Not too sure whether it was the bouncer I saw. I just saw "Ocean Wonders". You can contact Citistore in TKO on 2706 8068 to double check. Otherwise you can visit the nearest Citistore to you via this website www.hld/associate/citistore