"I''m just curious. How would one go about writing a script for a completely open ended game? And I mean COMPLETELY, as in there are several outcomes outcomes for each level and your mission progression is based on how well you do per level."

-Magic Card

I believe what you are describing is a "multi-linear" game, or a game with multiple endings and multiple ways to get there. You''re still stuck on a rail, but you can choose (or have your performance in the game dictate) which path you take. Examples: Several games in the Wing Commander series and Deus Ex. Examples of completely open-ended games: Morrowind/Daggerfall (Daggerfall came closer), and several of the Ultimas. Nethack, Angband and many "rogue-likes" fit this description as well (but have a more limited set of interactions).

To "write" an open-ended game, one must simply define the starting conditions, and how each object may interact. Then let the system go.

A fine example of an emmergent system such as this is John Conway''s famous (at least within math and game circles) "Game of Life".

How do you write a universe like this? Dream up a setting, some main characters to go into it, their likes/dislikes, and what they want to do... these factors ought to suggest one (more likely many) possible dramatic outcomes. The trick, of course, is implimenting all this in a digital medium. If you want some experience, start playing, and then "GMing" Pen+Paper RPGs (not minatures ones, like the latest D&D ruleset; these are too limiting).

Here is another thread with content germaine to this thread.

The idea of the FPS with levels dependent on performance makes me think of the random mission generator in Soldier of Fortune 2.

Maybe a system like that with the player performance influencing the "seed" for the next level? Perhaps not to generate an entire level, but maybe your kill ratio determines the spawn rate for the next level, your accuracy (or lack thereof) influences what kind of body armor they''ll be wearing in your next mission and so on.

In most cases it only takes very slight changes to dramatically affect the way a game is played and subsequently enjoyed.

That idea is at least as old as Wing Commander. Your performance in missions affected the course of the war. Often, it was just a gameplay reward system, rather than an actual cause/effect relationship. For instance, if you destroyed all the fighters on your patrol route without being destroyed, your cruisers three parsecs away would winn their battle, but if you ejected, they''d fall back. Some were more direct, like a freighter with secret tech needing escort to a research station, and its fate impacting the war effort.

If that''s the sort of thing you''re after, then you just need a bunch of branching possibilities, and then you can script a "cusp event" that will determine which path the player follows. These can be fights, dialogues, planning sessions, mazes, or timers, or anything else you can think of.

Your emphasis on the word "COMPETELY" in the first post was misleading. Sorry about the irrelevant posts.