The game sets out to be a historical RPG, and the text under the clever premise that the original authors were monks passing the long, dull hours of monastic life, complete with a foreward by the translator, and translators notes within the text itself. The game works in a way very similar to FATE, in that it's based on the invoking and evoking of Aspects, but it develops the concept in different ways. It's a bit more focused than FATE, and also has its own die scheme that is elegant in its own way.
Chronica Feudalis is a very tight little machine. It plays quick and easy, and with the FATE-like method of damage resolution, can be as forgiving or bloody as the group desires. Character creation is quick and dirty, with characters essentially picking up to three "mentors" that determine their collective skills at the start of play, such as Artisans, Courtiers, Knights, Minstrels, Peasants, Thieves, etc, in effect making each character a gestalt of the three classes chosen. The three mentors also determine starting equipment and funds, so character creation takes practically no time at all. This can be a little restricting, but individualization can easily be done through choice of Aspects, and additional kit can be bought during play. Of note though, the Mentors aren't just classes - they are expected to be brought in as NPCs from the start, helping the character to not just have a background, but to actively fit into the world.
I played quite a bit of CF over the years, and I'll be posting some of my house rules as I get a chance. Definitely worth trying out though, particularly with the hacks floating around out there. Some of my favorites are by Nathan at Platonic Solid, who managed to both expand the scope of play some, and made an excellent fantasy hack for the system. Posts of particular note are:
Chronica Feudalis Fantasy Hack - Wherein he sets up some basic premises for modeling orcs and other baddies.I got so much expanded play out of these extras that I would consider them essential for anything but the most historically-based games.
Chronica Feudalis Fantasy Hack: Scaling - Where he works out how to represent dragons and the like with the system.
Chronica Feudalis Fantasy Hack: Magic - which adds a flexible, fully functional magic system to the game.
Earlier, I called Chronica Feudalis the best game ever forgotten, and I think this is the most tragic thing about it. As much potential as it has as a simple system, the author seems to have forgotten about it entirely. The last post on the subject was back in 2010, wherein was Keller was beginning to hype the expansion book Noblesse Oblige. Some time thereafter he ran a kickstarter for Tech Noir, and the project seems to have disappeared off the map. A true shame.
I can only hope that he decides to come back to it one day. With several more years of design, and several additional projects under his belt, I'd look forward to seeing what he would do with the expansion.