Thanks for your feedback, Several! To respond:
I suppose that the number of objectives decreases but they grow in value. I was trying evoke a plant growing out of control and becoming ever more valuable - perhaps making it more dangerous would have strengthened that feeling.
I decided that describing the Objectives would fit best in the Objectives section - I didn't feel it worked well anywhere else but it could work better at the end of the section. Personally, I'm a big fan of narrative stuff and things like that just set things sparking in my brain.
Objectives do not remain seized - I didn't include that text for this reason. I did specify that points are only scored at the end of a round if the conditions are met, but a bit of clarification wouldn't hurt at all.
Anyways, thanks again for the feedback!