Possible Scenario:
Earth's forces have taken over one of the only weapons factories
on Trayng. Each of you must approach the factory from different
routes and raid it for any and all equipment you can find. Once
back out, proceed to the rendezvous where you can steal a hovercar
to make your escape.
Example briefing:
Falyn - On the Northeastern side of the factory is an air
conditioning vent. Work your way to it then pry it loose with
your energy blade. Once in, you should work your way into the
heart of the factory to where the Beam 44 Blasters are being
manufactured. Feel free to strafe the near-by Garrison before
proceeding to the garage where the others shall meet you.
Example Game:
Player starts off outside of the building (building take up most of map) one thing you should implement that's done in Diablo II is make building roof not there so once a unit has enter a building, he can continue inside the building without having to load the next level.
Player works his way past guards either sneaking past them or killing them with his energy blade. Once he gets to the building, he uses his blade to get in. (with trigger that opens the gate). I think their abilities should displayed on a menu that's a lot smaller than one on starcraft that displays other abilities, then buttons which can bring up stuff like a map, main menu, and character stats and inventory.
The fact that he can kill guards with his blade is because if two units are nearby and one spots you but other doesn't, only 1st will attack unless 2nd hears like a gunfight or something. Once in, he continues to work his way into the factory until he gets to where the Beam 44 Blasters (laser pistols) are and he takes one. Now, just like all RPGs, the player can go into the inventory and equip the blaster instead of the blade.
The player can then exit out of the installation and proceed to the garage. He got some experience points from finding the gun. On his way out he sees the enemy garrison and proceeds to it and he kills all enemy troops inside and nearby. Now he gets additional exp. for completing the additional objective. The player could have, however, passed the garrison up altogether and just proceeded to the garage and the end of the level.