Ship, I hope you didn't just play Ninja 5-0 on Easy. The "To Be Continued" message means there are more levels available, but you have to play them on higher difficulties. Beating Easy unlocks Normal and beating Normal unlocks Hard, each adding its own unique level, so in all there are 5 levels with 20 stages total. The later levels are much more fun and challenging.
Edit: Aww, beaten!
Also, I've got a suggestion for the show, but I'll PM you.
Edit: Aww, beaten!
Also, I've got a suggestion for the show, but I'll PM you.