The film’s conclusion—building a symbolic shelter of sticks—suggests that while there is no physical escape, there is a dignity in facing the end with honesty rather than fear. Cinematic Style and Symbolism
Justine’s struggle to maintain a happy exterior represents the "performance" required by society.
Justine’s depression has already prepared her for the end of the world. For her, the planet's arrival is a literal manifestation of her internal state.
The opening sequence acts as a dreamlike summary, showing the collision of planets.
Most of the film uses a jittery, documentary-style camera to create intimacy and unease.
In the second half, "Claire," the focus shifts to the rogue planet Melancholia as it approaches Earth.
As the world faces certain doom, Claire descends into panic, while Justine becomes eerily calm.