There has already been a thread like yours:
Will this game have achievements or bonus stuff?And I quite agree with h4tt3n here:
If this game is anything like the Samorost series when it comes to the underlying philosophy and "feel", I'd say it definitely wouldn't [have achievements]. It appears to me, that the games forged by Amanita Design pulls the whole game concept in an entirely other direction than the typical modern action game with features such as achievements, bonuses, and level unlocking just to mention a few.
Cheers,
Mike
But I'm not sure there's been an official word from the devs concerning STEAM and achievement possibilities