Most critics come away favourably disposed, if not excited. The praise gathers around Joel Edgerton, who plays two versions of the same man and, the reviews agree, keeps them distinct without fuss; Jennifer Connelly and Alice Braga are named as steadying presences alongside him. There is also approval for how the series uses its parallel-worlds premise: for regret and roads not taken rather than for spectacle, with a love story underneath the physics. Several reviews call it accessible, and one or two find it satisfying by the finale.
The reservations cluster almost entirely on length. Nine episodes is too many for most of the critics, who complain of padding, wheel-spinning and long stretches of explanation, and note the source novel is tighter. The spread is wide. /Film puts it ahead of anything the genre has managed in years; The Hollywood Reporter finds only one tone, a glum one, and IndieWire calls it handsome but shallow.