The first impression was of weirdness, slightly off-putting. The many twists in the plot are incredible and at the same time amusing and thought-provoking. A bold screenplay, a tight production, great artistry throughout. The troubled, helpless and hopeless main character hardly could find anyone better than Amalric to play it.
I liked the time travel especially, so well imagined and so revealing on some of the characters' backgrounds, on the (sad) destiny of the building, and on life in the longer run.
And, of all people, the main character goes off his way to save a goldfish. This will have paramount consequences. Remember: you'll never know when and how life challenges you.