Take a look at the Colossus battle http://www.youtube.com/watch?v=sXkOuSF-Yxc

This is the final part of the Colossus battle before you fight him from the inside. It gives a good idea of the scale of the enemy. Although whoever is playing the game in this video hasn't really understood how to play it. In that sequence you have to wait for the Colossus to do certain moves, which then gives you time to attack certain parts of him without being in danger of being hurt. And the earlier part where you initially see and are attacked by him is quite impressive too, but that is in the fist two parts of the video.