Very fun game but there are a few bugs, after finding the passage from Talos to Santorini I can't go from the Dam to Laurion, or from Santorini back to the Dam
Those aren't bugs, just content which hasn't been added yet. Those will be added in v0.4. Glad you're enjoying the game though.
I used to be able to do those things before finding the Talos to Santorini passage though, now I can't
There has never been a way to drive from the dam back to Laurion. Nor has there ever been a way to drive from Santorini back to the dam.
I swear there used to be, restarting now to check