Bought Frostpunk during the Steam summer sale and I LOVE it.
Takes place in an industrial revolution/steampunk setting when a sudden ice age happens. You people flee and start a new colony/city in the frozen waste, with this big ass coal generator in the middle of the city. I played through the first scenario, which took about 5 hours to beat. There are two more scenarios with more coming in the future. Unfortunately there is no sandbox/free build mode at the moment but the devs say there will be one by the end of the year.
Plays like a standard city builder/sim where you have to manage resources, space, and citizens, but with a few hooks.
Soooooo it's a tough call. Once you complete the scenarios there's not really that much else to do. It's a GREAT base game, a little lacking in content though. I would recommend it now for $25, just understand that for the time being it'll take you like 10-15 hours to complete the currently available content and you'll have to wait a little bit to get more. But personally, I think it's worth it because the core gameplay and presentation is amazing.