Is the time limit throughout the entire game, or just certain missions?

[CreepyCanuck]

Game looks interesting, and I'm curious to try it, but I feel like it's weird to advertise being able to explore, investigate and survive, if you have to do all that within 30 minutes.

Is the timer for everything, or just missions? Is there non-mission activity where you can explore and find what you need to craft and such?

[Savonir]

Time 'limit' is just an event, which you can survive or make the event appear later by building a specific item inside your base(no spoilers).
And timer is for everything, yes. If you don't want it at all, then I would suggest trying freeplay.

[Legileg]

You got it wrong. Every once in a while the Black Stalker finds you, then you have to defeat him or run away from him. Sometimes it is dictated by the plot, sometimes random, but not "every 30 minutes". It depends on how the player, how many days have already passed and how many special buildings you have built in the base. And it certainly is not a "time limit".