Ok first thing you have to do is make the player models and models 100 times smaller and the gun models ex. then you have to make the player movement very slow and the screen adjusted down correctly.
This will make very large maps.
Now for a different topic. A new game.
Other than that I am thinking about paying programmers to mod the engine to support map sizes of 4000 x 8000 instead of 40 x 40 and make lods so there will not be any lag.
I will pay them 2500 a piece to work on a project called project battlefield and we will be making Battlefield 1942 out of fps creator.
This means full vehicle support and massive multiplayer.
If you are interested in helping out pm me or post here.
Create build.