Matt Hurt’s review published on Letterboxd :
I appreciate the way Duck Butter explored intimacy and what it takes to truly let yourself (and your hang-ups) go in order to open yourself up to another person. In doing that, Duck Butter paints a pretty complete picture of Alia Shawkat's character as someone who struggles with intimacy.
But as interested as I was in Naima's journey thoroughout the movie and (to an extent) her chemistry with Laia Costa's Sergio, I really couldn't latch onto their relationship or Sergio's character by herself. They were very natural together and the dialogue reflects that as well. But I didn't feel that they had as strong a connection outside of the physical aspect of their time together.
Maybe that's the point, given Naima's reluctance and naiveté toward shared intimacy. But the climax of the movie kind of depends on the pair sharing a deep emotional connection and I just didn't get that impression when the time came.
I don't regret watching Duck Butter and I think it's the best performance I've seen from Alia Shawkat (who co-wrote it with the director). The movie has interesting ideas about intimacy and the struggles that come with it, but it doesn't explore those ideas as deeply as I would have liked.