[quote name='Acharis' timestamp='1330084353' post='4916168']
We can't We have no budget for this
I know that's the generally accepted answer, and that budget and developer time are both very good reasons for it... but sometimes good ideas can arise out of challenging commonly accepted ideas like "we can't make separate games adjusted for each player". I don't personally have any good solutions for doing so, but can you imagine how successful a game might be if they found a way to do so that was cost effective? I imagine the solution would lie with some combination of a very powerful procedural content generation system, dynamic difficulty adjustment, and a very effective analysis of how the player interacts with the game.
This isn't something I think would necessarily be wise to pursue, but the possibility is certainly an interesting one.
[/quote]
I think the best way to do this is to make the game easy to mod, (This goes for both singleplayer and multiplayer games), Look at games like quake, starcraft, skyrim, etc, For multiplayer games things become a bit more limited ofcourse(unless you allow proper mods) but a few things can easily be controlled by the server in a multiplayer game, (for an FPS you can let the server change things such as weapon stats, gravity, movement speeds, etc quite easily using for example scripts)
If you provide the tools then the players themselves will take care of the rest.
In the OPs case the easiest way would probably be to separate the engine from the game cleanly, make engine updates mandatory but stick with a fixed interface towards the game and then simply treat the game and mods in exactly the same way, older versions of the game can then be loaded as mods if players prefer a previous versions gameplay. (You could also release the source for the game portion under a restrictive license to allow the community to tweek it as they see fit)
[size="1"]I don't suffer from insanity, I'm enjoying every minute of it.
The voices in my head may not be real, but they have some good ideas!