What isn't stored in JJ2's memory? I can't answer either question completely, but I could imagine most of the things that need to be modified by a program are already there in memory.

To R3ptile: Seeing how pits work in other multiplayer games, I don't see a problem with it in JJ2. You lose a roast when you fall into a pit (not to mention all your ammo and powerups), which means extra danger and more skill needed to pass through routes near the bottom of a level. It could make levels more interesting if done well.

As for Team Battle, besides the fact the scoring works in reverse, it doesn't work 100% of the time and levels have to be made to support TB. A Team Battle prog would mean anyone could easily make a TB level. Start positions might still be an issue though if a level uses mostly MP start positions--I know I'm guilty of doing this with my own levels--but hopefully this can be worked around.