Continuity mistake: Tom walks into Anthony's memory. Anthony is sitting by the pool next to a table with two glasses of beer, which are 1/3rd empty. A few minutes later the memory is replayed, but this time both beer glasses are mostly full. (00:49:50 - 00:58:35)
Plot hole: In this Australian time-travel fantasy, a college student discovers a one-way time portal that allows him to travel one day into the past each time he uses it. While he at first attempts to rescue his girlfriend from a traffic accident that occurred a day earlier, he eventually travels back 50 years (one day at a time) to save his young grandfather. However, in order to go back 50 years (one day at a time), he'd have to repeatedly climb through the portal over 18,000 times. Apparently, it's not an issue, because the movie just glosses right over it in less than a minute.
Plot hole: The killer has been living in the (apparently big enough) crawlspace between walls and floors, for over a decade. There is no explanation (or rationale) given on how he moved the various objects inside every room, closed doors, fed when the house was not occupied, hid the various corpses and, silly detail, concealed his own BO and the stench of his own living quarters, which is something hinted at when they find out his hideout. It is explicitly said that he is agoraphobic and does not get out, ever.
Other mistake: After the medical student leaves the unconscious co-pilot to one of the other passengers to watch while he goes to the bathroom, she notices his hands grow cold after a bit. It is only then they realise he has stopped breathing, and then get a defibrillator out and are successfully able to use it to revive him with CPR as well. However if he has stopped breathing for long enough that his hands have started to get cold, he would already be way too far gone to be able to be revived.