If you're expecting gameplay that differs dramatically from the original you're probably in for a shock. Instead, Loco Roco 2 expands on the gameplay of the first in almost every direction, with a large variety of minigames and new gameplay features. The graphics have largely remained unchanged, but the world is now much larger, with plenty more stuff to do, see and collect in each level.
Environments are now more varied with many more types of enemies and friends to interact with. Controls haven't changed either -- the L and R shoulder buttons still tilt the world, while pressing them simultaneously will make your Loco Roco jump. Simplicity at its best.