I think you get two free hours for one child, for each adult who orders an entree at dinner. So, if there are two adults, you could get two hours for two children. I am not positive though. I ended up just paying for DD oop, rather than having dinner.
DD did not care for Camp Dolphin. If she hadn't previously been to Neverland at the Poly, she might have had a different opinion. Compared to Neverland, Camp Dolphin is tiny. They had two small rooms. In one room they did a craft project -- painted a plastic windchime (like you'd get from Oriental Trading Co) which I thought was really cute. They got to bring that home, no extra charge.
In the other room they had a tv set up with Wii and the kids played games for a while, and then they put in a movie for them to watch. They took the kids out of the club to get dinner. DD said they were allowed to order anything they wanted off the kids menu, and one boy even got a second meal after he finished the first one. She also said that she preferred the way they bring dinner to you at Neverland, and you get to eat on the bleachers while you watch a movie. I thought she'd like getting to leave the club for dinner, but she didn't.
She said it wasn't as much fun as Neverland, and she doesn't want to go back. She's also been to Simba's Cubhouse at AKL. She liked Simba's better than Camp Dolphin, but Neverland beats them both by a mile, according to her.