Something along the lines of "users", you could have passwords..... maybe you could build it into the code, like User <#name#> password <#pass#>. Or even better, relate it to a second file, user.txt, or something like that.

Along with these should come someway of doing properties. A way of setting a players HP, maybe these also could relate to another file, player.stat, where it lists everyplayers stats, maybe these should just be imbedded into the actual .ASL file...... but it's not up to me :)
Oh... and it also lists what they look like, ect...

It may also be good to have "custom" commands. Where the commands of the game vary with each player's "user" name.

I can't think of any others right now...

hope this isn't asking TOO much :)