First, I want to say awesome work, dudes. You've brought this thing a long way in the last couple years.
I've noticed a few minor things so far.
Running a pondmode sim with veggies set to kilobody point mode, slightly higher than usual gravity, low viscosity.
1. Veggies which are checked as "blocked" periodically become unblocked and drift to the bottom. Usually big ones, though I'm not sure if that's supposed to make a difference.
2. With top/bottom wrap off, some veggies and corpses manage to pass through the bottom of the field into a limbo area beneath.
3. Since veggies can occupy the same coordinates as one another, using the "planet eaters" function with unblocked veggies will cause the veggies to form into a superattractive clump which, like a black hole, sucks in every veggie in the field once it gets dense enough. This happens even with low settings for the "planet eaters" field [0.2, for example], and a side effect is that a "black hole" of veggies stops falling through the field and becomes "stuck in place".
I think that part of the problem is that veggies are permeable - if they were able to bounce off one another it wouldn't be possible for enough of them to cooccupy the same space in order to create a "black hole".
I wonder if problem #2 might be related as well.