Valley and continental glaciers differ mainly in area, thickness and speed of movement. The differences arise due to their location and relationship with underlying topography.
The primary difference between the two types of glaciers is size. Continental glaciers cover large swaths of land and extend over 50,000 km, meanwhile valley glaciers are confined to mountains and don't exceed lengths of 100 km. Continental glaciers are also far thicker, they bury the land in up to thousands of meters of ice, completely transforming the landscape. Valley glaciers, however, can be viewed as rivers of ice, far thinner with numerous tributary glaciers that join to form the main glacier.
In addition, continental glaciers usually move very little. Valley glaciers, on the other hand, have movement at the center, melting ice at the base lubricates their paths. The faster speeds of valley glaciers can be attributed to gradient, gravity works on the ice in the steep mountains while continental glaciers' velocities are almost solely reliant on friction. The nature of the two glacier types also means that they look very different where they terminate. Continental ice sheets break off at the end of continents and calve icebergs into the ocean, while valley glaciers melt and form river networks.