Completely unique(this review contains spoilers)
Movies have been around for more than 100 years now and during that period just about every conceivable plot has been tried. When it comes down to it, most movie plots are loose adaptations of one-another; for example Avatar and Pocahontas, Shawshank Redemption and The Great Escape, just about every romantic comedy ever, and likewise with murder mystery films. Even the sci-fi genre has staked out some broad categories that few of its members deviate from - space-sci-fi, time-travel-sci-fi, set-in-the-future-sci-fi, alien-sci-fi, etc. So when I saw Inception for the first time I was totally blown away by just how unique the plot was. I have never seen anything quite like it - not even since its release (except for a Rick and Morty parody, but that doesn't count haha). It is comforting to know that a truly unique movie plot can still pop up once in a while.
The premise of Inception is that technology has enabled people to enter the dreams of others. Once there, they can interact with the dreamer and plant an idea that will influence their real-world decisions. I won't go into the plot here, but I will say that even after watching the movie a couple of times I was still hazy on what the Limbo place was, and how anyone could ever escape from it. Fortunately, there is an Inception Wiki where it explains that Limbo is a kind of collective-unconscious place - even deeper than a dream. According to the Wiki, it is possible to escape Limbo by comitting suicide there, however this was not obvious in the movie. But anyway, I like movies that leave me with unanswered questions to ponder, so the mystery of how to escape from Limbo left a pleasant after-taste.