Is this an in name only sequal....

It's somewhere in between. The main good guy, played by Patrick O'Bryan returns as Spike.

It's kind of a direct sequel. Spike does return and the killer is stated to have called the phone number many times, but it doesn't really play an important role. The film is more about his astral projection and how he can go out committing these various murders while still being in prison at the same time.