Near the end of the song "Prem Se Humko Jeene Do" when Amitabh and Shashi Kapoor lift up their costume's donkey heads for a brief moment, it is clearly visible that they are not wearing the rest of their costume and are in T-Shirts. But in the next shot, they are back in the full donkey costume.
The song "Tune Abhi Dekha Nahin" takes place at night. Immediately after it, when Shashi Kappor talks to Parveen Babi, it is morning, But in the next scene when Parveen enters Amitabh's room, it is night again.
When Shashi Kapoor receives the letter that his mother and sister are coming, it is the middle of the night. In the next scene when Shashi and Amitabh are running from the sharpshooter, it is clearly mid-day. Immediately after that at the train station it is again midnight.
The sharpshooter guard is armed with a telescopic sniper rifle that needs to be cocked after every shot yet it is shown to shoot continuous stream of bullets like a machine gun.
Harish dies by crashing straight into a steam-roller, even though the steam-roller was moving extremely slowly, on an empty, straight highway and was a long distance away from him.