Well, think of this.
FPS Creator was made with DarkBASIC Professional. You can download the source to FpsCreator for darkBASIC Professional, for free. Then you could get the Enhancement pack, and compile FPS creator. By doing this, you would not only have the Game Creational engine that made FPS Creator, but you would be able to create whatever type of game you wanted with DarkBASIC Professional also!
So I would suggest getting dbpro and downloading fps creators source code. Then you could alter it to your liking, however, keep backups of it, incase you get too lost, and screw it up. NOTE: The source code is VERY LARGE! After i downloaded it, i noticed that it really was over 20,500 line! Navigating it, wont be easy. But you can still compile it.
I hope that helps.
Here is the link to the source:
http://darkbasicpro.thegamecreators.com/?f=upgrade_5_9
It has a few extra things with it to.
[CODE]