Steam Achievements are a kind of achievement that can be obtained when playing the Steam version of OneShot. Statistics for all achievements can be found here.
How to Obtain
Read books in the library.
Interact with all the "glowing" books in the library — these include the ones at George’s place.
"Don't do that!"
Interact with the smasher east of the outpost in Barrens with the lightbulb equipped OR combine it with the metal rod/crowbar.
Exhausting all possibilities, are we?
Attempt to trade all of the following with Magpie: lightbulb, strange journal, amber, tube of water, feather, bottle of dye, feather pen, wool (deny the first trade to get the t-shirt), novelty t-shirt, and seed.
Back to its roots.
Beat the game without saving by closing manually; i.e. beds only.
In the Glen, pick up the seed left by Maize. Go to the research facility at the South-most zone. Inside the rightmost building, there will be two robots - talk to the one in the middle and he will give you a tube of water. Go to the Refuge, equip your seed and walk left past the big guardian NPC that you first see directly after exiting Glen, and you will have access to the Garden. Plant this seed in the pot in the center. Go to the Apartments. At the end of the corridor, there will be a room leading to Mason. If you have planted the seed, he will give you dirt. Go to the surface of the Refuge, and go to the street full of vendors. The leftmost vendor will give you a free sample of a pill. Combine the pill and the tube of water to make medicated water. Go to the garden and give the seed the dirt and medicated water. Make sure you choose the “Return the Sun” ending and view the extra CG at the end.
Start a new game by deleting the fake save data located in your “Documents/My Games/OneShot” folder.
Acquire the novelty t-shirt from Magpie in the Glen by giving the wool but refusing the first offer. In Refuge, find the ram marking in the back alley (east of the entrance) and use the t-shirt on it.
Interact with a generator (e.g. the one you repaired in the Barrens, or the one in Glen), Silver’s battery in the lookout point (Niko will get shocked on the third interaction), or with the SRAM inside the secret room from the above achievement.