There's not much to say about The Culling, really. It's the kind of game that, if you like arena-based deathmatch shooters, you will probably like. If you don't like multiplayer arena-based deathmatch shooters, you will not like it. That's pretty much the delineation. 

Granted, as far as arena-based deathmatch shooters go, I like it a lot more than most, but it's going to be pretty clear when I describe the mechanics whether or not this is your kind of thing.