Even though I really don't understand the ending, such as yourself, I still love it. It's one of the few in a game that has kept me thinking about it years after I had finished it.
I'm not sure if playing ICO will really help you out either. As far as I know, it's an unrelated experience from Shadow of the Colossus. The only similarity is that they're set in the same world/atmosphere. I too want to know what it all means but I've never found a clear answer. However, I really don't think there is one in the first place; Team Ico wanted to keep us guessing.
Ico has some of Dormin inside of him, the babies are the new colossi, except they aren't rock made of earth, but flesh and bone.
Well, that's what I got out of it.
So you interpreted it as the horned children from Ico that are sacrificed in the castle are the descendants of Wander and therefore are flesh and bone versions of Colossi? I agree with you about them most likely being the descendants of Wander and that they probably have a little Dormin in them (the horns) but calling them 'new colossi' seems like a bit of a stretch to me. I never really thought about it but I guess if that is indeed the case (the horned boys have the spirit of Dormin in them) it makes sense that the village they live in would want to sacrifice them and get them out of their village. I wonder if the Queen told the villagers to do begin this tradition, or they just started doing it of their own accord. Do they even know the Queen is in that castle? Or is it just a convenient place to make the sacrifices, well away from the village itself.
I apologize if I'm asking redundant and already asked questions. I've never really gone out of my way to read those crazy in-depth summaries/theories that are posted here and on other sites.
Ueda isn't the person to give out explanations. He wants the player to come up with their own interpretation.
I don't think Wander had any kids. The ending is kinda saying: Yep, after all this, Wander still cannot have the one he loves, and is trapped in the Forbidden Lands for the rest of his life.
I think Dormin's spirit is just manifesting itself one by one. Or maybe it's that spell Emon cast on Wander that fused Dormin and him together.