In the beginning, after Sunil Dutt arrests the hostage taker, his uniform is soiled and dirty, yet when he returns home to greet his daughter it is clean and ironed.
Despite being locked in an airtight room filled with poisonous gas for several minutes, none of the people display any ill effects.
It is shown that Shakaal shoots DSP Shivkumar as he brings the gun out of the helicopter window, but during the close-up shot between DSP Shivkumar and the helicopter, that the helicopter window is shut.
During the final showdown, Shakaal floods the room with poisonous gas even though he himself is sitting in the same room and has no gas mask on.
Vijay knows exactly what each and every button on Shakaal's control panel does even though they all look the same none of them are labeled.
The self destruct lever in Shakaal's lair is conveniently located in the bottom of the wall and at the exact same place where Shakaal is thrown, instead of on his control panel which houses all his controls.