The original Chex Quest was a landmark “Advergame.” Included for free with Chex cereals and first released in 1996, it was essentially a full mod or total conversion built on top of the original Doom engine. It featured five levels in which you played as a man clad in Chex cereal-shaped armor, and you used a set of special weapons called “Zorchers” to zap “Flemoid” aliens back to their home dimension so they wouldn’t eat all the healthy foods like vegetables and…Chex cereal.
It was quirky, clever, and almost as fun to play as other classic first-person shooters thanks to the flexible power of the timeless engine it was built upon. Like many games, it gathered a dedicated fan base. The development team at Digital Cafe made a full sequel a few years later, and later some of those same folks made a third game and packaged the whole thing up along with ZDoom, making it easier to play on modern machines. If you want to read more about it or track down where to download the original games, the Wikipedia article is shockingly thorough, thanks to those dedicated fans.
