The best word I can use to describe It's Alive is "tepid." It's barely alive in terms of acting, visual effects, pacing and storytelling. Does that cover it? I think so! The worst part of this film is they never completely reveal the creature who is attacking everyone so viciously. In Hitchcock's films less is more, but with It's Alive less is less. Furthermore, the blood effects look like blobs of paint on the floor. I was surprised that Rick Baker did the effects work on this film. I'll cut him some slack since it was some of his early work. Thankfully, he got much better as the years rolled by.
Perhaps the weakest part of It's Alive is the script. This story line has been done to death and done better. Mom gives birth to strange creature who kills lots of people and dies in the end. The most frustrating thing about this is that It's Alive give no back story whatsoever. Is the killer baby the result of a pact with the devil? Space aliens? Living near a nuclear power plant? They never say a blessed thing. That's just plain lazy writing.
It's hard to believe but this tepid ilm spawned two sequels, neither of which I'm going to watch. So, if you're up for punishment, watch the other two and let me know what you think. Boring!
For more info check out the film's entry in IMDB.