This long chain of DTV sequels to the beautiful The Land Before Time has its ups and downs and this is one of the downs.
While not being awful it just disappointed badly. I had expected a lot more of the under water experiences which was promised in its title, but was only briefly shown at the very end. And thinking about how well the movie was animated in general the lack of contact with the under water world just made me sad. Most of the time nothing really happens on dry land, not even much of real threat or the life lessons these sequels normally did. It's just boring most of the time.
The new characters are all underdeveloped and that only added to the tediousness of it. Mo could have been so much more of an insight to the under water world and have more personality. He surely is the most memorable of this movie, but that does not make him a good character, because he was mostly just smiling and jumping around. The "Sharptooth Swimmer" could have been used a lot more, but wasn't.
The songs in general were forgettable and seemed to come out of nowhere. I am not a fan of TLBT take on musical numbers in general and this one proves it.
I have seen much more offensive attempts of sequels to great movies and I think many TLBT sequels have something to offer, but this one dumped its potential into the deep.