Liquidator is an unlicensed Russian Action FPS game. This game made on the Build engine and looks like addon or mod for Duke Nukem 3D.

In Russia in mid 90's, scientists finally achieved a major breakthrough in the field of teleportation technology into some new reality. In the best traditions of that time to commercialize anything and everything, enterprising people immediately opened their own agency and even began to take excursions to the new reality. But something went wrong, a dangerous situation was created. The result was a new, perhaps even very prestigious profession - liquidator. The reason for the need of such a specialization is quite specific. President Eltsin himself will tell you about it in detail in his special TV address: "...adventurers rushed in droves into the virtual world, but the unexpected happened. The creatures that inhabit the lower realms of virtual reality responded with a powerful confrontation, moreover, a number of aggressive groups managed to capture the teleportation facilities. At the moment the aggressors are preparing to take over our reality. The liquidators' task is to locate the fuel depots and destroy them".