ME:C is one of my unforgettable favorites. In a slightly futuristic society organized by castes, ever giving up more and more of its privacy and freedom of thought to the benefit of companies (rings any bells?), a country ends under the iron rule of an oligarchy born of the families to which said companies belong to. Freedom may be listed in the dictionary, but who holds the rights over that dictionary and the content of its definitions?
With such a setting, ME:C delivers a surprisingly beautiful, varied urban world in which you get to enjoy a game of parkour. Now the comparison is unavoidable with the original Mirror's Edge; while its predecessor felt closer to a parkour simulation, ME:Catalyst introduces a variety of surreal gadgets that help you navigate around the maze of the city of Glass, which you play in.
And yet, despite its predecessor being "truer" to parkour, I've enjoyed ME:C more; the city feels more lively and works like an open world (though limited to roofs and buildings' insides), areas of the city have a stronger identity to make them distinct from others, and the lore entries give you quite some insight to the life of Employs - yes, citizens hold a different name in their dictionary.
More than that, what I've enjoyed the most is how the game puts emphasis on being a Runner. Unlike its predecessor, you won't be using weapons to shoot people anymore, you're not trying to eliminate anyone on purpose to make it easier (except the occasional use of your environment, throwing an opponent off a building). Violence is put aside. Yes, you may kick, punch or throw opponents; at most you may want to knock them out, but that's all. Your main intent is to run, to be fast and to get faster; the main storyline forces some fights, but outside it - RUN.
It's a genre that feels, to me, sorely missing on the market. The immersion is great, the sensation of vertigo sometimes real; it'd be an immediate purchase for my game library if it could be on GOG!