The next kickstarter update for InSomnia has information about the games difficulty, and mentions you can purchase some new add-ons.
More information.Difficulty Level, Survival and Hardcore Gameplay\Add-ons
We want InSomnia to remain difficult as well as engaging. We’re fans of non-linear development, chance meetings and unique situations. When players begin to understand the underlying principles that drive the plot—or how to solve all available puzzle types—gameplay becomes stagnant. Challenging gameplay design makes players want to explore, and it forces them to carefully “read” the surroundings, paying attention to every detail. Achieving the right difficulty level truly immerses players into the world… and this is what we want for InSomnia. In fact, our goal is to create “thoughtful challenges” - fine-tuned gameplay that can keep players fully engaged for hundreds of hours. We’re not interested in “unfair hardcore,” which would only lead to frustration, and that is not what we want for InSomnia.
This is not to say that surviving will be easy, but it does mean that recovering health points won’t be overly complicated. Provided that stimulators are available, that is. Stimulators allow you to gain health points slowly over time. If you have suffered serious trauma, you’ll take progressively more time to heal, which is to be expected. If you ignore the wound, it will only get worse. On that note, hunger, thirst, and sleep deprivation are among the parameters you’ll need to keep track of at all times. Whenever possible, if you want to survive you should avoid eating rotten food, drinking dirty water, and entering extreme high or low temperatures. Healing burns is rather difficult, so keep a safe distance from fire. A punch or kick taken during a fight will not leave any major damage and you’ll be back to full strength in no time at all. But be warned: critical damage from a rifle can either kill you or require significant recovery time.
We know that having a proper balance between hardcore elements and fun gameplay mechanics is essential. We will strive for that balance with your support and more importantly, your feedback.