Visible crew/equipment: When Angel is fighting the demon, you can see an obvious camera and two hands in the bottom right corner. (00:27:10)
Visible crew/equipment: When Angel is fighting the worm demon you can see a cameraman in one of the shots. (00:27:05)
Revealing mistake: In the scene when Angel, a vampire, runs after the barman towards the end, after the barman has tried to pass on the demon to Kate and Angel stopped him, there is a mirror, and when Angel runs past it, he has a reflection. (00:38:20)
Continuity mistake: In the scene where Detective Lockely arrests Angel in the apartment, the window behind them shows that it's daytime. But when Angel jumps out the window, it's night time.
Visible crew/equipment: When Angel is fighting the demon a cameraman is visible rising on the lower right. (00:27:13)
Answer: Due to his epiphany, Angel basically had the 'true darkness' he worked so hard to reattain ripped away from him, like his soul was after sleeping with Buffy.