Tigris & Euphrates.
Tigris & Euphrates plays unlike any other game that I have ever played (well, other than Euphrates and Tigris Card Game), which says quite a bit as I normally own at least 75 games at any given time. On a given player's turn, they get two actions and with these actions they can either place a tile, position a leader, draw new tiles or play a catastrophe. Most of these actions will be taken positioning leaders and placing tiles.
Placing tiles is usually fairly straightforward - if you place a tile in a "kingdom" where you have the corresponding leader, then you get a point, if not, then whoever does have that leader gets a point. However, if you place a tile that will combine two "kingdoms", then the game takes a drastic change. This is called "external combat", and for each set of duplicate colored leaders in the new united kingdom, the duplicated leaders will fight to see which one stays. (Example: if there are now 2 red leaders in the combined kingdom, they will fight to see which one is the red leader of the combined kingdom). The leader that is banished is banished along with all of the tiles of his color in his original kingdom, and the player that won that battle will get a corresponding number of like-colored victory points. This happens until "external combat" is resolved by either there being no more sets of 2 of the same leaders in the combined kingdom or by the kingdom splitting back into multiple kingdoms.
Positioning leaders can also be somewhat tricky, as this can cause "internal combat" if you play a leader of the same color as a leader already present in the kingdom on which you have just placed. Essentially you are attempting to usurp their power, and so you fight using only red tiles to determine who wins. The winner gets to stay and gains a red victory point, and the loser's leader is removed.
Tigris & Euphrates has a lot of awesome features. The first one is the balance involved in the game. Throughout the game, you will collect victory points in 4 different colors, but your final score is the total of the color in which you have the least victory points - if you get 500 black and only 1 blue, then your total score is 1, and all of your extra black victory points do no good. This is a refreshing change from most games where you can build a strategy around only one facet of the game.
Another neat aspect of Tigris is simply how the strategy works. It plays so differently than any other game that I have ever played that it challenges me to think in new ways to attempt to determine the best move. Whereas, yes, it is a tile placement game in the same sense as something like Carcassonne, the strategy is much more intricate because of the placement of leaders. It is at least as important when and where you place your leaders as it is which tiles you play each turn.
Another feature that I like is how the combat works, and how important it is in the game. The combat is somewhat straightforward - whoever has the most tiles counting for them between what's in play and what they play from their hand wins, but even with that the combat is a big key in the game because joining two kingdoms at just the right time can quickly score a large number of points to add to a color that you have not scored on well.
Tigris & Euphrate's biggest downside is the learning curve. Because it is so different than most other games, it will take a little bit longer to understand how everything works in the game. This is not a big deal for people that often play board games (probably the people that follow this blog), but when they are trying to teach their friends a new game, this may cause some frustration.
Overall, I give Tigris & Euphrates a 9.0/10. It is a fun game that I think will leave you wanting to play it more.