Ice Age: Dawn of the Dinosaurs follows the same basic plot of the movie. Manny and Ellie are expecting their first child and the herd has different feelings on the matter. Manny is excited, but doesn't think he'll make a good father, while Sid and Diego struggle with their own problems. After failing to catch a gazelle, Diego decides to leave the herd, feeling he is losing his predatory instincts. Meanwhile, Sid becomes jealous of the baby, so he "adopts" three dinosaur eggs.
Throughout the game, you'll take on the roles of all the main characters, each with their own particular play mechanics. You'll spend most of your time switching between Sid and Buck, so it's a good thing their levels are the more enjoyable of the bunch. Both share the same underlying mechanics and though they don't deviate too far from the norm, the amount of exploration and general layouts of each level help it stand out - a pretty noteworthy feat considering the number of top quality platformers that call the PS2 home.
Although both share similar DNA, there's a noticeable difference between Sid and Buck's levels. Whereas Sid's areas play out like typical platformers, Buck's levels come off as a love letter to a couple of big Sony franchise. Imagine Ratchet & Clank's platforming combined with God of War's action and you've got it. I would pay to play a game based solely around Buck.
Sid also gets a chance to break out of the platform mold with a series of "ball rolling" levels similar to Marble Blast. If it isn't clear enough already, Ice Age draws on a lot of influences and does a great job combining them into one package.
As expected, there are lots of collectable items scattered throughout levels. Fruit serves as in-game currency and allows you to purchase upgrades and multiplayer options. Most of the upgrades, like giant cherries and gems, are purely cosmetic while others grant more health or ammo. One of the more interesting cosmetic upgrades is the fisheye camera. Oddly enough, it's a slightly better camera than the default one. Make it one of your first purchases.
Multiplayer supports up to four players and are based around the various play types that make up Story Mode. Although the number of play types found in Story Mode is impressive, the multiplayer variations aren't incredibly fun.