Guns & Steel
I'm a fan of Jesse Li's Flow of History and this is his earlier game on the same theme of civilization development. Here the large cards have two uses: one side shows a "Technology" (Agriculture, Alchemy, Overseas Trade et al), while the other is a resource. A key part of the game is thus managing your hand of cards and deciding whether and when to use the Technology or the resource.
Players buy new cards from an array and the cost of a card depends on how many others are adjacent to it. Thus, buying a card will make others cheaper. This may be good for you, but you don't really want to make things easier for your opponents...
There are two decks in the box, each providing a different view of progress through history with slightly different rules. They can be used separately or mixed to give a third flavour to the game. It's all clever stuff that will keep you thinking throughout.
For 2-4 players, aged 12+, playing time 60 minutes: £12.00 (£10.00 without tax outside the EU)