Great Game...but when does it end?

This game is a lot of fun and I remember playing it as a kid at the arcades. Good graphics and no glitches that I experienced. The one complaint is when I got to the last level and finally beat it (after many attempts) it took me back to that level again when I wanted to continue playing! I figured it would start over or start a new campaign. Are there any updated campaigns for this game?

Maxedwell about SkySmash 1918, v1.3