Frostpunk is a post apocalyptic world overcome by a severe ice age, where your small outpost of civilians is trying to survive the harsh conditions against all the odds, huddled beneath a huge generator, their only means to overcome the freezing conditions. Playable as both solo or co-operatively, there are a number of scenarios to test your ability in what is essentially a worker placement game with many moving tracker boards that you need to maintain and stay on top of. 
The harshness of your predicament is reflected in the game difficulty, in what is a real challenge to survive. You will be balancing many life threatening issues such as warmth, hunger and sickness, while aiming to maintain hope and keep discouragement at bay, allocating civilians to collect resources, constructing shelters and other useful buildings, while firing up the huge generator. There is a brief but thematic story being told across the daily revealed cards, and the scenario ramps up its problems for you to solve as each day progresses.
Part of the survival process is going to be developing and improving your society to cope better with the future issues. Initially though the need for resources is high just to stay alive, but as these are somewhat finite, decisions are constantly required to maximise the potential of what your have, such as whether to develop technology or initiate new laws, go on expeditions, or build new structures out in the snow, however there is never enough time to do everything you will need, and so it becomes a huge balancing act.
The toughness of the game is likely to split opinions. The challenge, even on the first normal scenario, will take time to learn and overcome. Whilst this seems to be deliberate, i am unsure why easier and more introductory play modes were not introduced so as to gradually uplift the challenge, scenario by scenario. That said there are a number of alternative set up option cards which will change what you start the game with, and some randomness is always built in with the snow tile lay out and which civilians, laws and technologies are available. It should also be noted that giving yourself a starting boost is extremely simple to implement and some fan made easy scenario starting cards are already available, and as such you can easily create your own difficulty tweaks. Whilst the game is designed for a solo player, I found it works well as a two player game, as there was enough tracker boards to split between players, and it welcomed discussion of our plans, plus you get your own set of one use civilian cards to work on. 
Why i chose not not keep it …
As a survival worker placement game with a strong theme this is a great but really tough balance game, and the core box components are really good, with wooden resources and meeples, many tarot size cards and great artwork. There are some drawbacks though, as there is a lot of initial game set up required, and each scenario will play long, with a lot of moving parts to balance, and i felt this was a tad too many, somewhat trading enjoyment for mechanisms. You have to dedicate a long session to set up and play a complete scenario making fairly inaccessible to land on the table. Comparable games are This War of Mine and Robinson Crusoe, and it is one of the best of its kind, however it is a really tough challenge.
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Expansions
The core set is pretty much all the game you ever need and represents almost all the gameplay elements too. However there was some kickstarter expansion content available to look for (my additions highlighted green = own, blue = part owned, red = not purchased) :
Frostlander
A mix of new cards to bring variety to your game decks, and wooden tokens to improve the look and feel of your game. In my opinion this was the only expansions i really felt i wanted, although i would definitely question whether i needed it.
Miniatures Box / Resources Box / Timber City / Dreadnaught
Boxes of miniatures to make your buildings 3 dimensional. The miniatures and resources boxes bring plastic representations of your buildings and resources, while the timber city contains wooden building representations, and the dreadnaught is a massive plastic train miniature that features in one of the scenarios. I honestly prefer the game set up without all these extra buildings, and finding each individual item each time almost seems like extra work really. The building tiles you get and play out anyway are more than enough for me.
Playmat & Generator Wash
A large snowy playmat on which to set up your outpost, a nice touch but nothing overly special in terms of artwork to look at, and i did not add this. The generator pre-wash shading is very nice, adding a darker and more worn look to the huge tower which i really liked, but it is not that hard to do your own wash in reality.