I'm pretty sure this was in the 1990s. I saw a review for it in VideoGames and Computer Entertainment and later acquired a copy of it (probably through illicit means given my habits back then). It was over-head viewpoint, maybe with 2-D graphics for the fixed viewpoint. You were fighting various gangs, I'm pretty sure in a post-apocalyptic landscape. The one enemy that's stuck with me through the years is yuppies in tennis outfits who use their racquets to hurl grenades at the player. Other than that, I think it was the usual mixture of melee weapons and guns. It was one of those games where dozens of enemies attack at a time. I think they contrasted it to games like Unreal which had much more intelligent enemies, but could only have one or two active due to system limitations. The other thing I remember is that there were different areas you could complete, with a "hub world" from which you could access the other areas. I want to say the review specifically called out the "hub world" concept.
It was on a PC, probably Windows 3.11 or Windows 95, although it's possible it ran in MS-DOS. The last thing that I recall is that I think the title was three words, something like "Kill Them All" (although a search for that just gets me a modern zombie shooter).