What's the point of achievement in a DRM free game? Unless the Galaxy client (is it out yet?) that i would gladly use instead of signing in thru the browser, then they may perhaps allow tracking of achievements in a DRM free game. If there's tracking, would you call that DRM free?
Achievements don't have to be done through an online system... Everything can be done from in the game itself & for some people there is a point to it because they like the satisfaction that comes from completing achievements and "beating everything".
As Speex has already stated, there was an achievement pane in the 35 minute demo, so unless something has changed there, it seems like achievements might have its own tab you access from the main menu or perhaps even a sub-menu when you press "Esc" whilst playing.
Although personally I prefer stats over achievements. Tell me how many monsters I've slain, how much total damage you've dealt, what % of the game I've completed, how much money I've lost/earned through Gwent, how many times I've gone for a romp at the brothel.. etc. I find those kind of stats far more interesting than just set in stone "You won 100 Gwent matches" kind of achievement stuff.