In Kleiners Adventures, you will start in the garage by your car as Dr.Kleiner in the year 2002 while Xen's portal storms come into Sack mesa just as you arrive to work. You find military, scientists, and security guards all dead and you have to find your way to safety, but some soldiers still stand. You might find a gun on your way exploring the destroyed facility. The military is NOT your enemy! You will fight through aliens alongside with the military through buildings, outdoor environments, and all the way to the other side of Sack Mesa to regroup with a group of guards, and scientists that wernt evacuated with everyone else. That is your way out of Sack Mesa. (You cant just leave from the garage because the door gets busted)
this is really only for testing purposes. and to show you how different it is from what you've really seen