I've seen Inseminoid, Galaxy Invader and Embryo. Galaxy Invader was a micro-budgeter that was a staple on Ned the Dead's Chiller Theater. Embryo had Barbara Carrera, the actress I always thought looked like an older Olivia Hussey. Inseminoid I don't remember much about except it was British and set in outer space, and sort of an Alien rip-off.

Which Impulse did you see? There's the one with Tim Matheson and Meg Tilly, and another one with William Shatner and Harold Sakata. Both are worth a look.