Besides this game having the ugliest box cover I have ever seen (background looks like 90s powerpoint; probably why its out of print), I thought it was a good game! I have never played #Caylus, however the general consensus is that CMC plays very similar to its predecessor, but quicker and with less going on. At its heart it is a worker placement driven by money that allows you to act and resources that allow you to build. The buildings you then build also create more spaces for your workers to "work". You and your opponents are attempting to help build a castle as well with the resources you gain. Helping to build the castle rewards you with prestige tokens that not only act as a method of gaining points, but also function as the game-end condition in that when these tokens are depeleted the game ends.
I would like to give it another go, but overall I thought it was fun!