Shoot them. Shoot them dead. And then kill them.
I can't lie, this game scares the crap out of me. The ruins, the enormous lakes, the castles... When you know you're not alone. In the lakes, besides the sea-serpent colossus, there are fishes and sharks, who scare you. I personally have always been like that... Too many things scare me easily. This being-alone in such vast places scares me. And their culture is scary. The buildings and all. The creatures are scary. Hell, even the little deers scare me when I'm running and they ram at me.
Basically, evertything is scary in here, I find this game a lot scarier than many survival horrors, like Resident Evil, Silent Hill, Alone in the Dark...
But the game isn't all about horror! Only the bow maneuver makes up for everything in this game. It's VERY fun to use bows. You find, in the land, lizards and fruits, which if you eat, they'll give you a stamina and health bonus. You have to kill the lizard hitting him once with either your bow or sword. Same goes to the fruit, except you don't kill it.
When I was fighting my 3rd colossus (cuz the first ones are more of a tutorial) I realized that this wasn't gonna be a game that you can opt to either shoot them dead or climb them to kill them faster. And here I was, thinking that to climb them, I'd have to hit their legs enough times for them to fall and then I could climb and hit the weak spot and that's it. Well, turns out it took me 10 deaths to realize it wasn't gonna be like that. I found that the world was my weapon. I could climb on the buildings near the arena, so the colossus would hit it and drop it's sword! And then I'd jump into his hand. There's a lot of other stuff, like using fire to scare them away to an edge which they would fall and break their armor, and running away from them and while on the horse, look back and shoot their eye so they couldn't see and hit the wall and be all exposed. But enough of that.
Yeah, so I'm in his hand, now what?? Now I didn't know what to do. But then he started moving his hand. I tried something crazy: Jumping from it. I did it and then I got to his shoulder! Well, then you know what happened (I raped him).
This is one game... Everyone should have.