Peter Ericson’s review published on Letterboxd :
The sequel to the marvelously entertaining "Iron Man", "Iron Man 2" is a relative disappointment. Sure, the requisite action, humor, and character development are all there, but where is the inspiration and sense of freshness that characterized the first movie about Iron Man? At least Jon Favreau’s return as director ensures that the overall tone of the picture remains consistent with that of installment number one.
"Iron Man 2" contains several well-executed, engaging action sequences. The Monaco Grand Prix sequence, for example, rivals the climactic battle of the film in terms of how exciting it is to watch. At the other end of the spectrum, the indoor fight between Iron Man and soon-to-be War Machine and the scenes leading up to it register as juvenile—silly, almost—despite the fact that there is a reasonable rationale for including those scenes (in the face of his deteriorating health, the protagonist lets himself go at his birthday party).
The film suffers from at least one major problem: it lacks focus. In all honesty, "Iron Man 2" plays too much like a setup for "The Avengers" and not enough like a self-contained entity. The plot is unfocused and overstuffed, and the pacing could have been better, what with the movie taking a while to get going.
Matthew Libatique’s slick cinematography emphasizes a realistic look for the proceedings, which serves the film well. While the special effects are generally solid, there are a few instances in which the effects work is less convincing than it should be. The score, composed by John Debney, is energetic and gets the job done, although it doesn’t offer any particularly memorable cues.
Robert Downey Jr. is perfect as Tony Stark, just like he was in the previous installment; confident, charismatic, and with a terrific ability to deliver his lines flawlessly. Playing Pepper Potts, Gwyneth Paltrow handles her part nicely and with gusto, although the script (written by Justin Theroux) does not give her that much to do here. Don Cheadle turns out to be a fairly good replacement for Terrence Howard in the role of James “Rhodey” Rhodes; however, I would have preferred to see Howard in the role, for the sake of consistency and because I liked his softer, more restrained take on the character. In Scarlett Johansson’s capable hands, Natalie Rushman/Natasha Romanoff becomes an intriguing character whose screen time is, alas, limited. Sam Rockwell is deliciously slimy in the role of Justin Hammer. As villain Ivan Vanko, Mickey Rourke finds the right balance between convincing and over-the-top acting. At first, I was not convinced that Samuel L. Jackson would make for a good Nick Fury, but he has since grown on me and certainly brings the required authority to his role. In addition to directing the film, Favreau has a surprisingly big role to play in it, appearing again as Happy Hogan.