There is no such thing as "in-game achievements" which are different than Steam and/or Galaxy achievements. What the OP is talking about should be labeled as something else which describes it accurately and avoids muddying the waters with confusion.
Honestly, I don't get it. How would you call something that's labeled as "Achievements" in the game (like in Shadow Warrior or ELEX) while the game doesn't support Galaxy achievements? If you're talking about something that "resembles" what achievements are, like in Indiana Jones, I could agree, because that's "just" a completion rate with challenges that give you various points. But that's how achievements work, usually, and that's why it's on the list.