Nice idea, just not one that's executed well at all.
'The Cat from Outer Space' is mundane. The concept of an alien cat invading is cool, but they choose to do it in a way that is boring - the cat, Jake, speaks via voiceover only, so there are many shots of the cat just staring whilst Ronnie Schell speaks. That just doesn't work, to get attached/become interested in a character you need emotion and/or expression... you get none of that here. I never cared for Jake, and that's coming from someone who loves cats.
Also with the plot they spend most of the time focusing on the cat helping the humans with dull things, like betting and freezing people. Quite inconsistently too, there's a number of times where the cat could solve their problem instantly but they avoid using him for some reason. It's only at the end when they, truly, tackle the overall story arc - which itself is held back by the (understandably, I guess) lame special effects.
Cast-wise it's very flat, none of them are particularly bad but they all give forgettable performances - even Harry Morgan (Stilton), who has done some fine things for Disney in these early decades.
I can think of at least ten worse live-action flicks from this studio up until 1978, but that's not to say this is anything worth watching - it isn't, unfortunately.