Also, if you're asking if Pree's health is meant to go down, you're probably doing something wrong. You have to wait through the intro until it says 'Press return to skip', then press return. It should start working from there.
Erik pointed out the problem to me a while ago. If a variable doesn't have an underscore in front of it, it will disappear and won't be saved by Algodoo. (e.g. _B2HP would be saved but B2HP wouldn't).
I'm updating all the Marble Siege 1 courses after Marble Siege 2 is done to fix this.