Shadow of the Colossus spoilers:
I saw lots of people write that Shadow of the Colossus made the Colossi seem sympathetic and killing them felt bad. I completely disagree. My thought process went:
1. Gee, this land is really barren, there's hardly any animals or plants and no humans. There are some ruins however. The Colossi probably destroyed the city and all living beings.
2. Oh, there's a Colos - shit it's attacking! Why?! I haven't done anything yet!
3. And now the protagonist died. Fucking Colossus. A giant violent thing mauling a tiny human boy who has done nothing.
How to make the Colossi sympathetic:
1. Once upon a time the Colossi lived in harmony with animals and people.
2. There was a coroviru I mean a plague or a war or an invasion by evil beings or something. The Colossi tried to protect the people and animals and all, but in the end all the others died and only the Colossi lived.
3. You go there and see a Colossus
4. The Colossus is grieving in front of a mass grave. It notices you, gets jumpscared, and backs away. Clearly fearing you and being wary of you, but wanting no fight.
5. You chase the Colossus a few meters while it backs down, but then it hits a wall (a ruin wall or a mountain wall or whatever). A few pieces of stone/rocks fall down on the Colossus when it hits the wall to show how powerful it is to make the walls crumble. The Colossus also seems irked and in a little pain when the stones hit it. It lets out a cry of pain. (not severely hurt, but think if someone slapped your arm)
6. The Colossus gets irritated, and starts making warning moves and sounds, but still doesn't attack. It looks and points away as if to tell you, "Leave! Go back the way you came!"
7. You still attack it.
8. Fight.
9. In its dying breath it crawls on the ground towards the grave before fainting in front of it.
Think of the flying Colossi. They could have just flown away. They could also just kidnap the girl and carry her elsewhere forcing the boy to follow or lie in ambush and steal the sword so the boy couldn't fight them and find them. Or the fucking Gorilla. It could have stayed in hiding, but no, it just suddenly attacks out of nowhere.
There could have also been a double Colossi fight. You fight against one Colossus, then when it dies it cries out calling for someone. And then a second Colossus arrives, sees the first Colossus, panics, rushes to take the injured Col into its arm, caresses it, then when the first Col dies in its arm, it gets sad first, then looks at you, gets angry, and attacks. (A double Colossi fight where you fight against both at the same time would also be cool, jump on a horse Colossus and then jump from it onto a bird Colossus etc. Or two bird Colossi and while you are 20 meters up from the ground flying on the first one's back you try to jump onto the second bird's back.)
You don't need speech or anything to convey that. Just looks, gestures, animalistic cries are enough.
Now that I think about it, it would have been cool if there was one moment like this with one of the Colossi, the gorilla one for example: if the player gets caught by a Colossus, the Colossus slams him into the floor/ground. The boy is alive and conscious but his health is very low and he can barely move. He slowly struggles to a sitting position. Meanwhile the Colossus raises its fist/foot, but stops as if to think, and lowers it back to ground as if it wanted to give the boy one more chance to surrender and leave. But then the boy takes his sword into his hand, and slowly raises to face the Colossus, and points the sword at it. At that moment the Colossus lifts its fist/foot again, and smashes the boy dead.
Shit, I should be a video game writer. I can imagine that scene in my head. It's so cool. I wish I could show you.
I feel that the Colossi wanted to die since they were part of a being who wanted to be reborn like Voldemort. Maybe they only fought to test the boy whether he was strong and good enough to be a vessel. I guess people thought "A being alone in a destroyed place and not wanting to go down easily = sympathetic".
I would have wanted to post this on the reddit Colossus forums, but they'd have probably downvoted me.