I've played through the entirety of Episode 1 yet I didn't unlock any of the achievements. What gives?

Got same problem, didn't get them even after second walkthrough.

Opened a support ticket but have yet to receive a reply.

Same problem here.

Just to give you guys an update. I reported the bug on Mantis and GOG eventually confirmed it's a problem with the game code. They've already informed Telltale about it and will let me know as soon as they hear back.

I was hoping that the release of Episode 2 would fix this but I can confirm that's not the case.

I got them for episode 1 but not 2.

Got the Ep.1 achievments but not those for Ep.2. Thought I might just not have had Galaxy running while playing the first time, but got none the second time around as well.

Never got any achievements for Episode 3 either. I made sure I had Galaxy running before I started the game even.

Has anyone tried emailing telltale support... we need to get this fixed. They worked for EP1 for me but that's it. I'm not going to play until this is fixed.

For me they do not work.
I've played through EP 1 and halfway through EP 2... no achievements were unlocked.
So I guess the problem is still there...

New patch says fixes for achievements... haven't tried it yet though.

Seems the achievements are working now - got one yesterday for (re)completing Chapter 1 of Episode 2.