All Survivors Guide
Olaf Heraldson: Unlocked by default, he's a really nice survivor to start with - especially early on. He stars with a can of gas and if you use him to replenish fires or generators, they'll get a boost in duration. Pretty good overall!
Irma Dillinger: Unlocked by default, she's good because she doesn't need to be fed that often. Decent stats as well.
James Abrams: Unlocked by default, he's the weakest of the three in my opinion. He becomes more useful later on when rooms won't all be heated, but there's nothing a good jacket and closing all doors can't handle. He's also way too slow.
Radj Shumpur: How to unlock, Smoke 10 cigarettes during a single game in Challenge mode. Easy to do if you have the cigarettes. Try to use them before using a first aid kit as each one drops health. Radj is not one of my favorites. He needs cigarettes to operate (starts with 5) and his stats drop a bit slower. However, he has poor cold resistance and is not that good in the later stages, despite his decent speed.
Ben Perez: How to unlock, Break six objects in a Challenge mode game while under the influence of the "Burst of anger". He's a generally good survivor since he needs less resources to make repairs around the base.
Mary Stone: How to unlock, Cook all foods available during a single game (on any difficulty mode). These are the things you need to cook: Frozen Vegetables, Instant Noodles, Potatoes, Instant Soup, Coffee Beans. She is a good survivor as well since she has decent stats (although a slow runner). However, she's great because of the Nutritious Protein Shake (a food item) that she gets when cooking. So, with her, keeping your survivors well fed is a lot easier.
Casper Jackson: How to unlock, Find all the tools in the game in any difficulty mode. The handyman of the game, he's really good to have around as he's very fast, but unfortunately has horrible cold resistance. His bonus is that of starting the game with some tools: a toolbox, a hammer and a shovel. Not extremely useful in the long run.
Olga Kramer: How to unlock, Refuel generators 100 times in Challenge mode (cumulative). It's easy to unlock her when you have a gas can and find a room with a barrel: you can refill it endlessly there and refuel the generator until you get her. Easy-peasy! She is extremely useful, especially later on in the game because she "sees" all the objects in dark buildings without the need of a flashlight. However, despite her bonus, she is very slow and has very poor cold resistance.
Emil Gustav: How to unlock, Complete the first zone in Challenge mode without going to sleep. He needs less sleep than others and restores faster. This is a good thing to have when you are surrounded by anomalies, but there are better survivors out there...
Katashi Hayashi: How to unlock. Use a first time kit in Challenge mode 100 times (cumulative). He's a very good survivor that constantly replenishes health without any particular items needed.
Natalie Shelter: How to unlock: During a single game in Challenge mode, use the saw to destroy 9 crates. She crafts better tools that last longer. This is a good survivor to have around.
Nicole Steelman: A really good character with good stats. She starts the game with a pistol and 4 bullets.
Martin Brown: Another useful character whose main strength is going through doors without the need of tools (keys or otherwise).
Philip Strauss: The in-game doctor, he's not very good at resisting cold but starts the game with a First Aid kit, can heal any type of problem with it and he can come out of a coma without an Adrenaline shot.
Ronald Witkes: He is slow, but a great loner: his Stamina and Satiety decrease a lot slower than normal when he is alone. Great for multitasking!
In-game Items
In this game, you can achieve the very same task using various items. Selecting the right item is exceptionally crucial, since some of them are more essential in the long run than the others. You will discover the majority of these through playing the game, however I will make it a lot simpler for you by sharing some examples of items you should focus on using:
For fires, attempt to use rotten wood initially, coal 2nd and just if you lack choices-- slabs. Coal lasts longer and slabs can be used for fixing and crafting, so are exceptionally important.
When you can fix with a hammer, do it rather of the repair work packages (which work as not whatever can be fixed with a hammer).
Exact same opts for locked doors: attempt to save crowbars for later on and use the keys as frequently as possible.
In the end, explore various items and see what works best for you. Keep in mind that the simplest way out is not constantly the finest, specifically early on in the game: you'll require your items in leading shape later on when things get even more challenging.