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's not nearly as amazing as it was when it was released.
This is our current soundtrack. It may or may not change in the future. "Oslo by night" by xhale. "Hundred Miles" by alexey v. "Weird view" by alexey v. "Crocodile tears" by workbench. "Hospital" by Alexander Chereshnev. "Zspaces" by Zilent Zpott. Read the license agreement, if you have any further questions.