Bobby Rhodes, who played Tony the pimp in Demons (1985), returns as a completely different character in this sequel. Lino Salemme also reappears, this time as a security guard.
When the phone rings at Sally's birthday party, the receiver is clearly on backwards, which would prevent the phone from ringing. The phone is put back on backwards after the call.
When George stabs demonic Sally with a stand pole after she has chased him and Hanna down the rope onto the lower rooftop, Ulla's demonic corpse is nowhere to be seen on the lower rooftop where she was thrown by George one scene earlier.
The birthday cake shown at about 25 minutes into the film is not the same one we were shown at the start of the film, the hand-lettering is different, actually more legible than it originally was.