Currently, the waterpark is mainly complete, the theme park is nearing completion with some rides already testing and some still being built, and the aquarium which is one of theme park's flagship attractions, is still under construction and will likely open last as the "grand finale".
Sources: https://www.facebook.com/groups/congdongphuquoc/permalink/1408863012640307/ and https://www.facebook.com/permalink.php?story_fbid=1079228865790758&id=100011109640304 and https://www.facebook.com/photo.php?fbid=2547950582159429&set=a.1401184750169357 and https://www.facebook.com/photo.php?fbid=1508164679341253&set=a.105521912938877 and https://www.facebook.com/hung.phat.545/posts/1519252778239494