Why doesn't my final iteration look like it does in the Entagma Physarum video?

[Hmm]

Disclaimer: I'm a complete beginner to Houdini. This is the first tutorial I've ever followed. In terms of 3D, I'm only comfortable with Blender but not really an expert.

I followed this incredible tutorial series by Entagma:

 

However, in Part 3 the 3D animation they show at the beginning barely looks anything like the one at the end. It's more orange, The structure of the physarum looks sort of like bone in the start, but it looks more like someone squiggled in 3D at the end. And this is also the result I got. Even though they are amazing, they don't show exactly how to get that first animation at the start. 

Here's my end result: 

And here it is with slightly different settings: 

So my question is: how can I close that gap between what I have and how it looks at the start?