Played a 2-player game of Terraforming Mars this afternoon: it works surprisingly well with 2 players. It's not even less tense really, because those attack cards are much more worthwile, and drafting to block someone is much more relevant. Really love this game, and I got to win this time (pretty comfortably too). The thematic element is so strong, which is what really elevates those big eurogames (Agricola being the classic example) for me, even though I still like the themeless point salads like Trajan and Concordia too.