Adam Waldowski’s review published on Letterboxd :
When confronted with "no more than a hundred" orcs, two of our dwarf protagonists shrug and begin slaughtering them like experts playing a video game on beginner mode. Such moments forego the most basic realities, and they're ultimately what kept The Hobbit from working on film. This is pure fantasy, of course, but plot conveniences and improbabilities eliminate any iota of drama. Once members of the sprawling ensemble finally shed blood, it's jarringly false. These characters have survived the most ridiculous, physics-defying action in cinematic history. Now they can't dodge a sword in time?
Smaug's attack is an early high point. The titular battle which follows is endless. Characters we've spent no less than five hours with can't develop much when they spend the runtime fortifying walls or swinging blades. During their time off, treacly, teary-eyed farewells abound. All their work is for naught since Tolkien, per usual, always brings in eagles to save the day.
The visual effects, particularly on the giant orcs, are shockingly cartoonish. But at least and at long last, this is finally over... until they sell the rights to The Silmarillion.