For a screenwriter, adapting a book into a movie can be tricky business. What parts do you leave out? Do you split the book into more than one movie? How do you write fresh dialogue that stays true to the author’s voice?

If you’re the The Hobbit: The Desolation of Smaug’s four-headed screenwriting team of Fran Walsh, Philippa Boyens, Peter Jackson (who also directed), and Guillermo del Toro the answer, apparently, is to stretch a 300-page book into three movies, completely invent a new character, make up entire passages, introduce characters from later novels early, and otherwise leave nothing but (barely) the shell of the original story. How, in the wake of all that, Jackson still manages to create a better-than-average movie is as beyond me. But there it is.

Jackson’s first chapter, last year’s The Hobbit: An Unexpected Journey, was fairly criticized for being monstrously overblown, merely the set-up for what will (incredulously) wind up being an eight-hour-plus saga. (For reference, the entire novel trilogy of The Lord of the Rings is five times the length of the book version of The Hobbit. But the three-movie trilogy of The Hobbit will eventually clock in at roughly the same time as three LoTR movies combined. Egad.)

Fortunately Smaug benefits somewhat from including the real meat of Tolkien’s story. The movie is, on its own, very entertaining. Jackson has taken great care to present the world (if not necessarily the substance) that Tolkien created. The story of the Hobbit Bilbo Baggins continuing his quest to get to Lonely Mountain and face the dragon Smaug is still intact. And they still battle giant spiders and escape from the Wood-Elves dungeons in barrels. But what are marauding bands of Orcs doing here? And Orlando Bloom as the Elf Legolas? And who is this Tauriel character that Evangeline Lilly is playing? Answers? Tauriel is a creation of the screenwriters to give the film a female presence, the Orcs are brought in so all that extra screen time had some bad guys, and, hey, who doesn’t love Elves? All are reasonable decisions, certainly.

Jackson has always prided himself on presenting epic movies epically. His sweeping bird’s-eye-view shots are first-rate, as are the digital effects that dominate the proceedings. The acting, likewise, is excellent, particularly Martin Freeman as our hero Bilbo and Ian McKellen as the (alas, underused) wizard Gandalf. Plus– the vistas are sweeping, the action is tense and expertly choreographed (including Smaug’s finest moment, the barrel escape sequence), and the script, despite starting out a bit esoteric, quickly finds its way.

It actually seems like it would be more fair to give The Hobbit: The Desolation of Smaug two reviews; If you’re a Tolkien purist (or even a casual fan): 2/5 stars. For people just looking for a solid night at the movies, call it:

4/5 stars