Corrected entry: All of the animals realize they are trapped in the valley unless they can get to "the boat" before the area floods. This begs the question - where did they come from that led them to the valley and why not just go back the other way instead of making the pointless trek to the other side?
Corrected entry: Near the beginning, where Sid threatens to jump of the ice cliff, Manny and Diego are shouting from the ground for him to come down. Then about a minute later it cuts to Sid up on top of the hill, and Manny and Diego are already up there. It took 10 minutes for Sid to get up there but it took Manny and Diego a minute.