A quick perusal of the titles and descriptions might make you realize that they probably didn't sell very well not because of the AO rating, but because they simply stunk.
The controls stunk, and quite honestly, the storyline-though VERY loosely based on events in real life-just went flat right away after playing through the first level.
Players of Goldeneye 64 might recognize the look technique and I'll be honest, I stunk at that game for some reason.
