King of Thorn: Do I Have This Right? [Spoilers!]

This thread is one big spoiler so read at your own risk.

I just finished watching King of Thorn for the second time. I wanted to ask if this is what you understood of it.

Spoiler

The Medusa virus is the byproduct of an alien entity. That alien entity needs a host and can manifest the thoughts/desires of the host. The first host was a girl named Alice. Alice was housed in the castle facility where the cryo chambers where.

The alien entity decided that Shizuku is a far better host than Alice. Shizuku/Medusa manifest a replica of Shizuku's recently deceased sister, Kazumi, and puts her to sleep in the pod. When the cryo sleep is interrupted, Shizuku/Medusa rampage with the vines (reminiscent of the Sleeping Beauty story.) The dinosaurs and vines were also to protect anyone from reaching Medusa and pulling the plug, which Marco achieved in the end.

 

Yeah that's pretty much what I got from it too.