1. Bosses are really vulnerable to poison, especially from Advena Squirter zooids (because poison mines got nerfed, and no longer spew streaks of poison upon exploding)
2. With enough Spike zooids, you can move those spike balls that spawn in the environment safely, provided you do not go too fast
3. It is possible to take out Frakir's minions one-by-one before taking on Frakir itself, if you manage to worm your way around Frakir's area of aggression. Something to note: Frakir is most aggravated by your creature's core, so keep it close to the walls if you want to do this
4. Sniper zooid shots can pierce through more than one zooid, making them somewhat useful for breaking the internal structure zooids of enemies
5. Energy Leech's range is greater than that of the standard Leech's, so putting Energy Leeches behind a wall of structure zooids will still allow them to work, albeit at a close range. You can "stack" one row each of Leeches and Energy Leeches this way, rather than alternating on a single row. Just don't expect the Energy Leeches to work as well in this configuration, but you do get more attacking zooids. For the Energy Leeches to work well in this configuration, add Greaser zooids that buff the Energy Leeches.
Also, slight correction - those "green stones" have been confirmed by the devs to be creature eggs!
...which makes destroying them for nutrients/power-ups feel that much more gruesome. Such is nature.