Unfortunately there is a game breaking bug in chapter 2 in the scene, when you first talk to the mother tree and a cutscene plays.

After you return from the cutscene, the controls (except of the menu button) don't work anymore and you can't continue.

In the steam forum someone found out, that actually the game is wrongly checking for GOG galaxy and crashes while trying to send over the achievement data
https://steamcommunity.com/app/1067540/discussions/0/2794998378626735779/?ctp=2#c2794998399741504571

So, if you haven't GOG galaxy installed, you can't continue the game.

Hopefully there will be a patch soon - otherwise the game is unplayable without the external client software.

I got that bug. It's irritating, but thanks for tracking down the explanation. At least the devs acknowledged and prioritized it according to the Steam thread you linked.

Galaxy has received the patch already. It's now on version 1.9.
Offline installer should follow early next week.

I can confirm that with the newest patch the bug was fixed and I could continue past the cutscene.

Thanks!