At heart, Invasion of the Tinysauruses is a simple children's story where the main character lies. The character has to lie again, to cover up the original lie. The lies keep getting bigger and bigger, until the character finally admits the truth. Everyone learns that lies, even small ones, are bad.
The problem with the "lying is wrong" morality movie is that the main character doesn't actually lie. The movie acts like he did, but in reality, Littlefoot told the truth. So why is everyone giving him a hard time for lying?
Here's the situation. Littlefoot accidentally knocks the leaves off a sweet tree, way too early. The leaves fall to the ground, and they are demolished by a herd of tiny dinosaurs. When Littlefoot is confronted about it, he says the tiny dinosaurs ate the sweet leaves. Which is true. I guess you could say he lied by omission, by not mentioning he knocked the leaves off before they got eaten, but that doesn't make much of a difference.
All the dinosaurs overreact and start patrolling the area, hoping to catch and exile the tiny dinosaurs. Littlefoot makes friends with the tiny dinosaurs, and he feeds them on the sly. (That's a lot closer to lying than his earlier "lie".) Littlefoot's friends meet the tiny dinosaurs and have lots of fun with them.
The DVD skipped ahead, to the point where the tiny dinosaurs are exiled. They redeem themselves by returning to the Great Valley, just in time to save everyone from two smaller carnivores.
I didn't like the tiny dinosaurs very much, but I suppose little kids might be fascinated with them. It's sort of like Journey to the Big Water, in that how much you enjoy the movie depends on how much you like the cute new character.
Most people dislike this movie, due to the bad premise of tiny dinosaurs, and the storyline about lying, which wasn't well-done. For me, the saving grace of the movie was the subplot about Cera's father meeting an old girlfriend. It was hilarious to see the angry character get all lovey-dovey, and John Ingle did a great job the entire time. John Ingle was on both Days of Our Lives and General Hospital, so I have to imagine that love storylines were second nature to him.