So I've unlocked most of the trophies, all I've got left to do is collect all the feathers, wear some cape in every city, complete chapter 14 and escape somewhere. Thing is, I don't want to miss the last opportunity to get these feathers, really don't want to have to go through the game again just to get them. So, can you go back and explore once you've completed the story? or should I be going to get them at a certain point? thanks =)

Yes.  There's a "New Game+", so just bother with it when the story's done.

I don't know that there's a New Game+ (maybe there is), but you can definitely explore after you complete the story.

Yeah you can keep playing after you beat it.

And if you need a guide to find the feathers, here is a great one. I used it and it made things easier. You can even uncheck the feathers you find. And click a X to watch a video to show you where they are.

Cheers lads