Terraforming Mars is a Euro-style engine-building game where five players compete for victory points, most of which come from terraforming the red planet.

Each player plays a corporation, each of which have special powers. Players have five resources to collect:

1. *Money - which pays for everything
   

2. *Steel - which counts as 2 money for certain improvements
   

3. *Titanium - which counts as 3 money for certain improvements
   

4. *Trees - which can pay for some improvements or be used to plant forests
   

5. *Energy - which can be used to pay for certain improvements and is converted to Heat at the end of the round
   

6. *Heat - which can be used for certain things, including raising planetary temperature
   

Players starts with six cards which they can keep for 3 money each or discard. At the start of each turn players draw four cards and they can keep any of them by paying 3 money each.

During each round players take turns doing one or two actions or passing. One you pass a player is out of the round and there is a little bit of an advantage to being the only one with actions, though other times you want to get something done before other players.

In general a player's action is to play a card, paying the cost to build it. Cards cost money to build. Cards have tags. Some tags say that cards cost can come from another resource. A prerequisite tag might indicate that a card requires a player to have a certain amount of science or space industry, which other cards provide.

A card's effect is either one time, in which case the card usually also gives victory points; an effect that can be activated every turn, perhaps at a nominal cost of a resource like energy; or an ongoing effect like protection from certain attacks.

Some cards allow a player to place tiles on the board. Cities, research bases, forests, water (which in general go on water spaces). Forests provide victory points by themselves, by being next to your cities (any forest next to your city counts), and by raising the oxygen level. This makes a forest player fairly powerful in terms of getting VP but there are more cards to attack forest players than other players.

Mars has three terraforming tracks: oxygen, temperature and water (the last being a deck of water tiles). Once all tracks go to maximum and all water tiles are placed the game is over. Some cards require certain terraforming levels before they can be used while other cards cannot be used once certain terraforming levels are reached.

That's pretty much the game. You spend most of your time building up your industry, placing cards that increase your resource income (income is done at the start of each turn). More incoming resources means you can place more cards which give you more income until the end of the game where players are doing many things. Getting that income engine built efficiently is a key to winning.

I found the game to be pretty fun. Most of the theme comes from the cards and even then the cards really only have a name, picture, attributes, and a one-line description. Placing tiles on the map is pretty neat and shows Mars being slowly colonized and terraformed.

Depending on your card draw and choices there are different routes to winning. You can't be good at every resource. Donald was a forest guy so he played lots of cards that were animal and plant based. Shannon was an Earth-based corporation and focused on space (satellites, space stations and ships). I was sort of a mineral guy, extracting steel and titanium and playing lots of building cards.

There is not a lot of things you can do to other players. Some cards are "paid" with any resources on the board so you use them to take resources from other players. Placing tiles on the board first allows you to cut out other players from certain bonuses. Hitting certain terraforming levels gives bonuses so you want to hit those. But really if a player gets going it's hard to stop them.

Overall I found it to be a pretty fun game. Good theming for a Euro. Lots of cool pieces. Complex strategy.