And what become of her new straw hat that should have come to me?
I'm no Stewart Woods and I need a short list like this for my sanity. To the point, 'Euro-ness' in games is on a continuum and is a subjective classification. These are the things I consider when making that classification for myself. Any game could fit into any one of these guidelines and so it is to the degree to which a game fits them all that is important. Just remember, this is not spam... it's SPIM!
Scalability: is it just a matter of blocking a few spaces or removing/adding some tokens per player? how different does the game feel with different size groups?
Player Conflict: do all players get to finish to the end? how much can one player interfere with another?
consider the coin total secrecy rule in "Small World" vs attacking each other in said example. (coin secrecy is a way of discouraging conflict between the lead player and others who would have his head on a platter)
Interwoven Mechanics: are there various mini-mechanics for selecting turn order, acquiring/using resources, claiming something, moving on the board, setting up the board?
consider shipping, trading, settling, etc in "Puerto Rico"
Multiple, Balanced Paths to Victory: is there more than one way to win?
consider prestige, VP, goals, card points in "Race for the Galaxy: The Brink of War"
Hey, thanks for reading! Until next time, be a saint... what else is there?