In fact I had completely forgotten I had even watched this film until I came across it on a random film list. Colonia reeks of Hollywood phoniness, especially an overlong and rather unnecessary chase sequence near the end that has no other purpose than to make the film long enough to count as a feature length film.
Emma Watson can be a solid actress (see Perks of Being a Wallflower or The Bling Ring) but her performance is nothing more than adequate, and rather forgettable. Daniel Bruhl is solid enough, but it's obvious that both these actors are straining to bring depth and conviction to a flimsy screenplay. Michael Nyquist, however, is certainly chilling and downright loathsome, but even he is nothing more than a one-note villain.
It's also a bad sign when there's a sense the director felt the only way to hold the audience's attention is through endless depictions of abuse and horrific implications of child sex abuse, only to cheapen it when throwing in typical thriller tropes for cheap, ineffective, suspense sequences. It makes the treatment of the true story seem exploitative and disrespectful to the actual victims who had to live through this atrocity.
Colonia feels like a poorly written blurb you'd find in a history book in high school, and the bull shitted 5 page essay one would write just to get a passing grade. Since I had never seen heard of this true story, I was shocked to see how recent certain aspects of it was. But I'd highly suggest skipping this entirely, and looking into documentaries or online research, as this silly and absolutely forgettable depiction of true events should be skipped.