a gun that can make someone speak truth when shot

i dont remember much about the movie as i watched this around 10 to 15 years ago, below is a list of things i remember
1) a gun that can make someone speak truth when shot
2) a house sized CRT tv like computer that can speak
3) the villan has two heads and he can swap between them, one head is a good person and the other one is bad person, he eventually get rid of the good head
4) interstellar/interplanetary travel involved

Is this even a real movie or i’m trippin?