In its current state there are very few missions and you’re going to get bored doing the same ones again, especially as you don’t garner any rewards from them a second time through. However, once those millions of monkeys with typewriters start churning user-generated content, and people get to grips with the simple-but-powerful tools, we expect to see a lot more interesting stuff here. Once there are a gazillion X-rated ambulatory penis missions, this will be the natural conclusion of the original Spore game and, as Kieron said also the natural conclusion of its paralleling the history of mainstream videogames; welcome to the Little Big Planet stage.
LOL…I completely forgot about the adventures people are going to come up with using ‘adult’ creations. It’ll never make its way onto the Sporepedia which is thankful…although Youtube will be full of videos from these players. 😛