I was at a cousin's house during the summer. I was about 9 or 10 when it was distributed to NP subscribers and everyone had one. I guess I didn't get NP at that time, because I never owned it.
My cousin showed me how it worked. I was wondering around this town going "Where are the enemies?" Well you're in the town. Go outside. "What is this?" It's the world, dude, it's huge. "Whoa."
So I kill a few enemies. Using menus was weird but I caught on. Then this music popped up. I was now at Level 2. "Level? What level? Where is it?" No, YOU are Level 2. You power up over time while the world stays the same. "Fuuuuuuuuuuuu..."
Mind blown. That was a total revelation for me!

