Near the end, when Mario and Natalia are in the boat, it begins to lightly snow. A few minutes later, as they're walking along the waterside, there's enough snow to make snowballs. Additionally, in the early morning when no one else is around, the snow is not a pristine "blanket" covering the ground, but it appears as if dozens of people have trampled over the walkway and grounds.
(at around 4 mins) When the bar closes and the owner exits it, he pretends to take out keys from his pocket to lock the door. But, as the camera moves away, the actor portraying the owner of the bar, can be seen putting the keys back in his pocket without locking the door.