OMS: Unfinished Business is a mod for registered Wolfenstein, made by Majik Monkee. It was released on October 20, 2015.
Though not titled as such, it is the fourth and final volume in the Operation: Mutant Strike series.
It features 5 levels, all very large in size and quite difficult. These were made by ack. Unlike the three other Mutant Strike mods, the protagonist is good ole' BJ.