I came up with two possible interpretations of the "spinning top cliffhanger." They are mutually exclusive to one another.
The "Was Mal right?" interpretation:
TL;DR - When Mal jumped out the hotel window, she didn't die. She woke up. Dom is stuck in limbo, signified by the spinning top at the end.
TL;DR - During Fischer's inception on the plane, everyone but Dom (and maybe Taito) wake up. Dom is stuck in limbo, signified by the spinning top at the end.
The "Was Mal right?" interpretation:
TL;DR - When Mal jumped out the hotel window, she didn't die. She woke up. Dom is stuck in limbo, signified by the spinning top at the end.
- Assume the top falls over at the end of the film.
- Mal and Dom fall into limbo for fifty years.
- They "kick" out of limbo by committing suicide by train.
- Mal incorrectly believes they are still dreaming and jumps off the hotel ledge to her death.
- The plot pans out exactly as seen--a thought-provoking movie nonetheless.
- Assume the top keeps spinning at the end of the film.
- Mal and Dom fall into limbo for fifty years.
- They think they "kicked" out of limbo by committing suicide by train.
- Mal correctly believes they are still dreaming and jumps off the hotel ledge to her wakefulness.
- Everything we see in the movie is within Dom's limbo dream. This explains the "only in dreams" logic we sometimes encounter:
- Buildings impossibly squeezing in on Dom, who Saito amazingly saves at the last moment.
- Mal's impressively orchestrated suicide jump. Dom finds her at the opposite window.
- Wow! What a mindfunk!
TL;DR - During Fischer's inception on the plane, everyone but Dom (and maybe Taito) wake up. Dom is stuck in limbo, signified by the spinning top at the end.
- Assume the top falls over at the end of the film.
- Dom is awake before the plane ride.
- During the inception, Dom, Ariadne, Fischer, and Taito descend to the fourth level.
- Four team members and Fischer kick back to wakefulness right away.
- When Dom washes ashore, Taito is an old man because he entered limbo sooner.
- Taito and Dom realize they're in limbo.
- Taito shoots Dom and then himself, kicking them back to wakefulness.
- Dom reconciles old demons, successfully plants the inception, and finally sees his kids--wow, great movie.
- Assume the top keeps spinning at the end of the film.
- Dom is awake before the plane ride.
- During the inception, Dom, Ariadne, Fischer, and Taito descend to the fourth level.
- Ariadne had warned Dom how he may become lost in his limbo state.
- Everyone but Dom and Taito kick back to wakefulness.
- When Dom washes ashore, Taito is an old man because he entered limbo sooner.
- Dom loses track of reality in limbo (as Mal once had done)
- Dom dreams he wakes up with the rest of the gang and sees his kids.
- Wow! What a mindfunk!