Your last game was very good. If you wrote that feeling that you didn't really understand how to use Adventuron, then you should be congratulated.
Regarding your opening text being too long, it's good that you recognise that now. For me, I hate reading a long blurb at the start of a game, particularly if it's only background and not really relevant to the game itself. I just want to get in and play the game, not read a friggin' novel. If you can, try to give a bare bones introduction that presents enough of a teaser that it makes you want to play the game, then gradually reveal the story, and even the goal, as the game develops.
I'm really looking forward to playing all these games.