basic betrayal questions

[eastwind]

How do you get into this betrayal mode in the first place? I've seen messages on the federation screen about 0 betrayal, but that's all.

Also, I don't see any way of taking over a planet.  I can bomb them but all I could do with bombing was get the Thoraxians down to 1m ground troops (and no other citizens), plus put their environment at -2000, but I couldn't wipe them out (maybe they're special because they live underground?). I think eventually I bribed the burlusts to attack them, but then it was a burlust planet when I'd done all the heavy lifting (or dropping).

Are there additional options to invade a planet once you're into the betrayal mode? Not clear to me how in the game lore one hydra can invade a planet anyway, but I've gotten this idea that doing so has something to do with betrayal mode.

[TheVampire100]

You are not playing betrayal mode but federation mode. That's two totally different game modes.
The betrayal in federation mode works different. As far as I know but I'm not 100% certain is that once you do something unpleasant to races (hostile actions) that are already in your federation they will feel betrayed. At 100% they will leave the federation or worse you could loose the game.
Some actions like killing leaders of a race even if they are not in your federation will trigger betrayal points for all races (except the burlusts because they cheer on stuff like this). You can also not conquer planets on your own in federation mode. You are not a faction on your own because you represent a single person, yourself, in the game.  You cannot massacre a whole planet on your own and take it. What do you want to do with it anyway? Your goal is to unite all races not to kill them. Killing a race is always bad and only an option if you have to do ot for the greater good of the federation.

If you want to play betrayal mode, you have to start a new game, go to advanced start and selecet under the options that you want to play betrayal mode.

[eastwind]

Thanks -- but it turns out the most basic thing I was missing was that Betrayal mode is paid DLC that I don't have....

Doh!