Copper Country is about competing mining companies in 19th Century Michigan. Players train miners and send them into new mines, risking their lives to dig for valuable copper. Establishing an infrastructure around the mines will increase the number of shifts that each miner can work, and mitigate against some of the dangers.
This is essentially a game of "push your luck" - you are collecting resources and a supporting infrastructure to successfully mine copper in as many shifts as possible each turn, but each shift (production cards) increases the risk of unrest or death.
We played the advanced game, which added a ton of stuff; local business cards that add free actions, 19th and 20th century events which change the game state, and an end game resource bonus for the person who collects production cards with the most of a specific resource.
And this seemed to be the main problem. These extra cards added a huge degree of randomness to the game, and an end game bonus which was achieved (by me) more by luck than planning. I also felt that a four-player game meant the board was very busy and constrained, and I struggled with the rulebook as it explained basic actions in overly thematic terms. Finally, I think the "long" game was probably a few rounds too many.
So, it's certainly an interesting and thematic game, but I think it would be better with fewer players (my guess is three is its sweet spot) and the shorter game (fewer rounds) and without all the extra cards and events. I think it will then be a much more interesting and tight game.