There are 4 levels. The first is the first level (of course), the second is like the underground level. The third is another above ground level. The last one is like the castle. "Bowser" is actually like a muscular weird dude, but you don't really try to beat him. You go above him and get what looks like a grenade thing.... If I could read japanese, I could know what it said, but I have no idea. Fun, and annoying game.
*EDIT*
Here's the "boss" and that's the player at the top. There's another "you" down at the bridge.
And the last screen before the credits
