Custom IK setup for a snake-like character issues

Hello Peter,

Following your IK setup tutorial, I've set up the IK chain for my snake-like character (a part of it, its tail) like that:

https://take.ms/53JbyH

My model is actually a collection of models united into one. So like a toy thing, with many segments.

So the handle is on the last bone in the tail. But when I move the handle in the pose mode, I come across two issues:

1. The last segment of the tail seems very rigid, stuck to the previous segment, and they move together as one. You can see it here, there's no curve, no bending between segments in the tip of the tail:

https://take.ms/ahCrS

And in Blender you can see the borders of these segments and how they are arranged when I move the last bone:

https://take.ms/R71ok

Why is it not like that in Unity?

2. Another issue is, I can't rotate the bones via IK handle. I mean, when I choose Rotate tool and rotate the handle, the handle rotates, but this doesn't translate to the bones, to the mesh.

3. And last one, when I move the handle, the whole chain is kinda broken in the way it's bent, like that:

https://take.ms/MIBJl

So it has this very hard bending point after the first bone, and then other bones, though connected to the chain, behave very differently.

I mean, what I would love to achieve is the smooth bending of the whole chain, you know. So that the whole chain would curve like a snake's body, without such a sudden break in the chain like there is now.

Could you give me recommendations on how to achieve that? What do I do wrong?