JacWac’s review published on Letterboxd:
I haven't seen too many Jake Gyllenhaal movies, but I could tell that this was by far the best performance of his career to date. He had many factors to consider when deciding on taking this role. "Gilroy's directorial debut." "Leaving the A+ project of 'Into the Woods'." "Having to lose 25 pounds." Which you can really tell, cause he looks like a whole different person. He really did transform into Lou Bloom and did it perfectly. As for Lou, you're not sure whether to applaud him for his work ethic, or to insult him on the methods he has for his work ethic. At one point, I actually felt threatened by him. No jump scares, no gore, it was just a man. I never felt so good about having fear. Incredible. A definite must watch for Gyllenhaal fans alike/everyone. I support him now, and you should too.
UPDATE: I wrote this back in November, before Into the Woods came out. Before I knew it would end up being more like a C+ project.