Being based on the same engine as Marathon 2,
it shares a lot of code with that game. While Marathon 2's
source is readibly available, the same cannot be said for this game.
That said, the demo version does contain most of the function names.
Holding the Command and Option keys together while clicking on the
"Begin New Game" button brings up a prompt to go to any level in the game.
This also works for doing either a single-player or a network game..