Taken outta the profile and placed as news:
A little more about the InGame Mission Editor (IGME): This clever feature essentially defines and edits entity placement using a file separate to the compiled .bsp. What this means to the player is that you can create and play and infinite number of different missions within the same map. Eventually, you'll be able to define bot (drone) behaviours, objectives, SAM/AAA batteries and a whole lot more! And this is all done in-game, so no modding knowledge required... mmm... tasty :).