It turns out that Joyce, who is called on the phone by Andrew, is in on Milo's plan. Milo even says so later. So Andrew should have known he could not get away with pretending to mistake Milo for a burglar a few minutes after this. It is strange for Milo to bring up an unknown policeman (Tarrant) instead of reminding Andrew of Joyce when he pulls out the gun.
(at around 48 mins) When Milo throws Andrew's manuscript into the air, the Edgar Allan Poe award statuette is on the mantel; the trophy then disappears in the next shot of Andrew, only to reemerge a few moments later.
(at around 18 mins) While Wyke is clearing the colours in the snooker game, he jumps from blue directly to black, even though the pink is on the table (in a previous shot), and in potting order comes between blue and black. Then, when the black is potted, the pink is nowhere to be seen.
In the final scene, Milo tells Andrew that he asked the police to meet him at 10:00. He looks at the clock, which is showing 9:45, and says that they should arrive in about 15 minutes. A few minutes later, he looks at his watch and says that they'll arrive in "a little over 30 minutes".
(at around 1h 2 mins) When Wyke "shoots" Tindle in the head at contact range with what is supposed to be a blank cartridge, Tindle simply faints from fright. In fact, the hot gases, explosive particles, wadding and minuscule barrel debris from a blank-cartridge shot to the head at point-blank range would certainly have given Tindle quite a serious wound, possibly even a fatal one.