In Friedrich, you will be commanding one of 4/5 armies and trying to conquer your enemies' cities to become the ultimate ruler and come out victorious.
There are a few things that I enjoy about Friedrich, the main one is probably the simplicity of the rules and the focus on combat strategy above all else. The board is divided into squares each having a different suit (hearts, spades, clubs or diamonds) that match cards that you have in your hand. Your combat power is a mix between how many troops your general is commanding (which starts as a secret), the number on the cards you have matching the suit where you're fighting from and how many of those you're willing to sacrifice.
There are a lot of places you can move to, and different ways to get there, some quicker, some slower. Here lies the tactical complexity that makes me enjoy the game so much, you need to pay attention to how much your opponent is fighting in a certain suit, and try to strike them when they're low on cards of that suit. So you'll want to coordinate with the other players (who are not fighting you but are not fully allies), launch "fake" attacks or even sacrifice some troops in some areas of the map to gain a tactical advantage in another. I've played the game many times and we always spend a lot of time even after the game debating strategies. That for me is proof of a good strategy game.
Overall I feel pretty good at the end of a game of Friedrich, but there are some parts that might not strike you as great. Everyone gangs up on the same person and yet it's not cooperative. This leads to whoever plays Friedrich having to be on super high alert, since they have to be aware of the strategy of another 3 players. It's hard to be Friedrich. We've sometimes had another player play Hanover (a small part of the Prussian empire), which helps Friedrich but can be boring for that player, since Hanover is very underpowered versus France. In my experience, with equally good board game players that play the game casually, it's highly unlikely for Friedrich to win.
There's quite a bit of randomness involved. There's inherent randomness because you're drawing cards, but hand management is a huge part of Friedrich's strategy, so even though you can be unlucky at times it doesn't bother me much. The randomness that kind of sucks are the cards of fate. These are cards you draw every turn and affect the game. You can be doing very well and suddenly you're taken out of the game, or completely nerfed. And the worst of it, honestly, is that it's not only bad for the "attackers", but can also be terrible for poor Friedrich, who's usually already struggling. On the other hand, it's the only way Friedrich has to win, hang on until the cards of fate kill everyone (there's an offensive Friedrich alternative win condition, but it's also hard.)
It's a 3h game (if Friedrich doesn't mess up badly) that I'm always happy to put on a table. It needs players with similar levels, otherwise, it can be a total destruction and it's not fun for anyone.
Some of the bad things I mentioned are known and there have been efforts to overcome them with a game called Maria. I've only played it once but didn't enjoy it as much, to be honest. It adds extra mechanics that in my opinion ruin the elegant simplicity of Friedrich.