Peter Ericson’s review published on Letterboxd :
After the relatively weak "Harry Potter and the Order of the Phoenix", returning director David Yates conjures up some movie magic and proves to be a worthy Harry Potter director after all. This consistently engaging, generally well-paced film nicely balances its mature themes of friendship, loyalty, growing up, love, and evil with humor that temporarily cuts through the appropriately dark and somber atmosphere; however, the movie is somewhat unsatisfactory, in part because it touches upon but does not explore a number of intriguing things.
The cave sequence is stunningly realized, including Dumbledore’s impressive fire spell. Thankfully, the very tragic thing that happens at the end of the film is tactfully handled and suitably emotional. The first part of the end credits has a mesmerizing quality to it.
Top-notch special effects that enhance the story rather than overshadow it; characterization and story come first. Splendid cinematography.
Daniel Radcliffe, Rupert Grint, and Emma Watson are not exactly outstanding in the lead roles, but the chemistry between them is unmistakable and more than makes up for their minor acting deficiencies; the effect of the Felix Felicis potion on Harry makes for some memorable acting from Radcliffe and Grint has plenty of hilarious moments as Ron. Tom Felton gives a nuanced performance as Draco Malfoy. Evanna Lynch is absolutely perfect in the role of Luna Lovegood. Jim Broadbent, Michael Gambon, Helena Bonham Carter, and—as always—Alan Rickman also deserve a mention for their excellent performances.
Based on the novel "Harry Potter and the Half-Blood Prince" by J.K. Rowling.