I didn't know that 'Insomnia' was based on a Norwegian movie of the same title. Otherwise, I would have watched the original film first. What convinced me to watch this one was the cast that included three super-talented actors and the director Christopher Nolan ('loved his 'Memento'). Thus, my comment is pretty much just about the movie rather than how it compares to the original.
There's really a lot to like about. This isn't merely a 'catch-the-bad-guy' thriller but a character driven psychological drama. It starts as a who done it, then turns into a how done it to why done it to what are you going to do about it. While it is the complex characters that stand out, the details of the murder case(s) are very well presented and the layered twists add well to the plot. 'Insomnia' is fascinating to look at. The production design is of very high quality and the cinematography is breathtaking. The attention to detail and the emphasis of the visuals that make the viewer experience Dormer's sleep deprived world is stunning. Incidentally, I was watching it very late at night and perhaps that is the best time to watch it.
Nolan's style of execution is remarkable. Daylight is used very effectively as a character of its own. In a way, it's the antagonist of the movie that leads to Dormer's mental 'deterioration'. It's a dark movie set in constant daylight. Then there's the clever use of fog and floating logs which in a way act as pathetic fallacies. Blood also plays a symbolic role. The quietness of a cold and gloomy Alaska is both intense and chilling.
Al Pacino proves again what an excellent actor he is. It's amazing how he eerily looks the part with bags under his eyes, a clumsy gait, stooped shoulders and a continuous expression of fatigue while he dives into the depth of an extremely complex character. Robin Williams skillfully downplays his part as the latently manipulative Finch as he takes advantage of Dormer's vulnerability. Hillary Swank brings an air of freshness as the rookie detective who also has to make a difficult decision towards the end. Maura Tierney makes very good use of her few scenes.
On the flip side, it may seem as though 'Insomnia' loses focus in some scenes as it appears to derail. Of course there are different ways of looking at this. The ending feels rushed and is very predictable. Also Williams's Finch could have been more developed considering the important role he has. Nonetheless, it's a well-made film. I intend to watch the Norwegian version to see how it compares but on its own, Nolan's 'Insomnia' is a fascinating experience and the cast and crew deserve all the praise for finally putting it all together.