Rip-offs just aren't as blatant as they used to be. Take 1981's Inseminoid for example -- a sci-fi horror film about space miners that come across an alien that impregnates humans (available on Netflix streaming under the title Horror Planet). It's basically Alien with a budget of $1.98 (although, it is a British film -- what's the conversion on $1.98?)
It's so low-budget, in fact, that there's one main set in the film that's just an unlit stage containing a handful of TV monitors and what appears to be a professional soundboard standing in for some high-tech computer controls. The walls aren't visible, and the objects in the room look like set dressing for a minimalist high school play. The movie is awful, but there's an odd sort of conviction about it that makes it watchable -- or maybe I was just waiting for another moment to come like the one in which the alien rapes a human with a plexiglass tube of what appears to be ping pong balls rolling in snot. (I didn't get one.)
Check out this poster after the jump, though. If that image doesn't sell you a ticket, I don't know what will.