Operation: Black Mesa is a total Source remake of Half Life: Opposing Force. Using the Source engine, the developers plan to recreate the Black Mesa research Facility as it was seen by Corporal Adrian Shephard of the H.E.C.U. Half-life: Opposing Force is still an amazing game, although it is not nearly as amazing as it was when it was released.
Concept art for various Opposing force locations.
Wow! It looks like you just painted over an already made level!
Oh damn!
Took me a while to realize that it was just concept art , and not an actual map