When James is talking to his mother at the window, they are both holding cigarettes, but in one cutaway his mom is holding a glass of wine.
At the very end, when James and Zoe are at the beach watching the oncoming firestorm, it gives the impression that they remain alive right up until the fireball engulfs them. In reality, at the speed the firestorm is traveling and the sheer amount of heat being pushed well ahead of it, two unprotected people standing in the open would have been incinerated and the shoreline would've erupted in flames long before it hit the beach.
In the beginning when James is driving, there is a radio announcement made with the speaker stating that his call sign VK which belongs to Australia (the range of VHA-VNZ). This is an amateur radio call sign which means he shouldn't broadcast on AM band but he could, with proper equipment, since it's end of the world. The call sign of VK6DF actually exists and belongs to someone.
Despite the heat and shockwave traveling towards the protagonist on the beach, the clouds in the distance do not move. They should have dissipated from the oncoming heat or have simply blown away and yet they do neither.
The film gives the impression that the northern suburb of Malaga (the location of the ice rink) and the southern suburb of Willeton (the location of the library) are relatively close together. These suburbs are approximately 25 kilometers apart, and traveling between the two in the fastest way would require driving through the (burning)Perth city center.