We found 11 Bit Studios' Frostpunk an equally excellent and challenging experience (read our review), but with update 1.1.0 that just saw release you'll be able to challenge yourself even more with Survivor mode, where you're abilities as a leader will really be tested. Here's what the press release had to say:
"If you find Hard difficulty all too easy, this new mode will be the true test of your ability to survive the winter apocalypse! You can pause the game only by opening a menu - there is no active pause whatsoever! - and your progress is only saved upon exit, so all your decisions are final. The difficulty level itself is also more rough and demanding - meeting the people's needs or balancing the delicate economy of your city will be even harder."
Oh, dear. You can find out more about the update in the dev diary below, and if you're interested by the game you'll be glad to know it's currently enjoying a 15% discount on Steam.