I played it so much when I got it that I got an achievement for playing through all the stages in one sitting, that means I didn't save and quit the game at any point.
If you ignore the hype it's a fantastic game that can only get better, there are annoying flaws such as repetitive gameplay and annoying micro management in the space phase, but the game is more about exploration and creation.
This is my tribe hunting and killing an epic version of my T-Rex...
http://www.youtube.com/watch?v=lvcQwzgR-oE