Distrust

Each character you unlock requires a different set of conditions to get and can only be done in Challenge mode (you can unlock 2 in Adventure, but I'm not sure which ones or if it's just 2 total). You start the game with 3 possible characters with an additional 12 possible.

Must be completed in a single Challenge game
Natalie Shelter - Saw 9 crates (More Wood achievement) - can also use the axe on the crates

Radj Shumper - Smoke 10 cigarettes - can be performed by different characters (My Poor Lungs achievement)

Ben Perez - Break 6 objects while under the Burst of Anger madness condition (Repairs Needed achievement)

Martin Brown - Finish four zones without breaking a door (Handle With Care achievement) - doors must be either lock picked or opened with the key ring, not sure on if shooting counts or not

Emil Gustav - Don't sleep in the first zone (Insomnia achievement) - drink coffee, eat coffee beans, or eat protein bars to get stamina back up

Must be done in Challenge mode, cumulative over all games
Olga Kramer - Refuel generators 100 times (Tesla achievement)

Katashi Hayashi - Use 100 first aid kits (911 achievement)

Might require Challenge mode, not entirely sure
Nicole Steelman - Get the second bad ending (Fatal Shot achievement)

Mary Stone - Cook all 5 different foods in one game (Rich Ration achievement)

Casper Jackson - Find all tools in the game - can be done in multiple playthroughs (Collector achievement)

Phillip Strauss - Finish the game once, any ending (This Is The End! achievement)

Ronald Witkes - Get the Good Ending (Selfish Act achievement)


To be safe, you should just play in Challenge mode all the time if you are going for achievements. Adventure mode is limited on what you can get and unlock.

Bleep bloop. Achievement unlocked. Hope this helps.