Though "The Streets of San Francisco" gets better as it goes on, the pilot episode is very weak. Malden and Douglas are rougher around the edges and their delivery is off, the actual story is slow to develop and ill-fated lovers Robert Wagner and Kim Darby have absolutely no chemistry together.
If this had been pared down to a regular episode, it might have been a good story. However, as a bloated two-hour movie, it suffers from bad pacing and weak performances. The abundance of flashbacks to the romance between Wagner and Darby is bad enough, but when those flashbacks are absolutely dreadful, it makes the whole thing seem ten times longer than it is. Throw in that Kim Darby is a terrible actress, and you almost want her to just hurry up and get murdered so we can get back to the story.
But it's not all dreck - the movie is almost saved by the finale, when Stone and Keller confront the killer in his cellar lair. It's creepy and the ending is very downbeat. It could have been a great hour of TV, but as a movie-length episode and a pilot, it isn't very memorable.