I don't think the baby was necessarily planet-sized, I think it was just closer. ;-)
But apart from that, I felt exactly the same way about the movie when I first watched it (just about a week ago) and hence decided that the best way for me to fully understand the story (it's a actually very complex) is to read the book. I only read a part so far, but there really is much, much more to the story than the film itself gives - which is exactly what Kubrick intended, by the way. So, if you're out for a really good story, I recommend you by the book. It really is a good read.
To everyone who has enjoyed "2001: A Space Odyssey" and/or found it even a little confusing, I highly highly recommend this.
To really get 2001, I recommend reading the book by Arthur C. Clarke.
*Edit: Plus, for Bladerunner of course the book too.
Read the book.