Somewhere out there are doubtlessly many games that would cause my jaw to drop, and chances are I'll never hear about them, much less make the time to play them. It's simply luck of the draw that I saw a forum post years and years ago where someone was talking about this awesome freeware game called Desktop Dungeons and decided to try it out.
Desktop Dungeons is fortunate enough to have gotten a lot of coverage, be it from word-of-mouth or conventional games media. Others are not so lucky, even if they may have awesome games that they've put every bit as much love into.