I grabbed the pdf to play with my 5-year old son and after one game I already feel I got my money's worth. Nothing earth shattering inside as expected, just some super simple rules, some nice art, and some good advice/tips on how to run a very free-form story that a young kid will enjoy. I particularly liked the section about avoiding saying 'No' and getting in the habit of saying 'Yes, and...'. Also contains some story ideas in case you're struggling that can help get creative juices flowing just by reading through them before starting. During character creation, reading off the list of 'skills' a robot might be good at helped us get the ball rolling on the skills my son ultimately picked, and following the advise to ask a lot of questions questions about 'What is space like in this story?' (Are there aliens? Are they good or bad or both? Do you have a ship?) quickly got us started on a random adventure we made up on the spot about him buying his ship and traveling to a friend robot.
FWIW, I was debating the pdf vs a book and I'm glad I just got the pdf. You won't need it to reference anything at all during game play, and the story ideas/art can all be read/shown from a tablet or phone very easily. Save a tree and money and maybe get the coloring book instead if your kid really enjoys the art.