the key thing about Between Two Cities is the partnership element (but with one winner).
This. What Jamey said. I'll say something similar, but rather longer.
B2C has a great many similarities to a great many other games. For example, there's the game where:
- you take a card (or a tile or two in the case of B2C) from your hand
- the other players do so at the same time
- you put the card you took on the table in front of you
- you pass the rest of your hand to another player
- there are three rounds
- you score differently for different card types: one type rewards you for having the most of that type, other types reward you for forming sets,...
- scoring also depends on interactions between cards of different types.
The core of B2C is its insanely great twist on the partnership mechanism. That core is surrounded by other mechanisms, many of which are familiar to many BGGers.
I do not know of any game for which it would make sense to say: I have AnyGame, therefore I don't need B2C. B2C's core mechanism is... how to describe it... let's call it a game-changer.
ps the game described in the list above is
Spoiler (click to reveal)