So how are the updates done?

It's already the latest version when you download it, and the new SDC is getting pretty close.

How will the pre-orders for Rebellion work?  We we need to download from Game Spot or will we download from here?

To add to that, will Sins/Entrenchment/Diplomacy continue to be used via what used to be Impulse, or will they be switched over to Stardock's new basic platform?

Right now the plan is to do Rebellion beta access direct download from Stardock only.

We will continue to issue updates to the existing titles via the GameStop app and via direct download from Stardock, as needed.

But soon we can remove it. Right?

That's entirely up to you. 

Awesome.

I bought Trinity from Impulse a while ago.

Can I download my copy of the game without Impulse?

Nope.  Not yet.  Once the new Stardock Central is released to the public, then yes you could.

If you bought it before Impulse was sold to Gamestop back in spring, you should be able to download Trinity from the store site now.

I can't check trinity, but those of us that bought each version separately, the store it says to register on impulse and download with that.  See below.

Product: Sins of a Solar Empire - Diplomacy Serial: XXXXX-XXXXX-XXXXX-XXXXX-XXXXX-XXXXX Downloads: Please use Impulse to register your serial number and download this software.

Product: Sins of a Solar Empire: Entrenchment Serial: XXXXX-XXXXX-XXXXX-XXXXX-XXXXX-XXXXX Downloads: Please use Impulse to register your serial number and download this software.

I know I purchased well before the sale of Impulse to GameStop, so I have to assume that even those that purchased Trinity would be given the same message...  Unless you guys are playing favorites with the Trinity owners. 

Boooooo!

I have the same problem...I would add that I also cannot download Galactic Civilizations II or either of the expansion pacts and I know I got all 6 purchases before Gamestop bought Impulse...

By chance, is it because I already have the games installed?

As a small side note, I find it strange that Galactic Civilizations (just Dread Lords) is not listed as a game, but as "other"...expansions are listed under games though...

No. Currently only the newest release/bundle of each game is available for direct download (Sins Trinity, GC2 Ultimate, etc). If you have the games and their expansions individually, you'll need to continue using Impulse until we're able to make them available in that format.