Grain Rot Walkthrough — Tutorial Quests to the Second Floor and the Ancients

A GRAIN ROT walkthrough is really two routes woven together: the vertical descent loop through the Deep Layers, and the quest chain that slowly reopens the Outpost you are living in. The community progression guides agree on the broad shape, and this page follows it in order: finish the tutorial, learn Spark and the elevator modifiers, rescue Biggy's friend, recover the Second Floor Key, push through Tink and the upstairs systems, beat a Corrupted Elite, then follow Dr. Quill to the surface. Anything drawn from a single source is flagged as unconfirmed so you know which numbers to test yourself.

This page is compiled from the credited community documentation and the official Steam listing; details that rest on a single source are marked to confirm.

The Opening Quest Chain

The first hour is scripted. Biggie and Murch walk you through cleaning the Outpost, repairing a wall, and crafting two simple structures, and the game only hands you the Deep Layers once that chain is complete. The quests are called Clean Up, Fixer Upper, Break & Build, and Explore the Deep Layers, and none of them can be failed or missed. That matters because the chain gates everything after it, including the rescue quest that eventually unlocks the second floor, so a player who never finishes the housekeeping will not see the later objectives at all.

Phase	What you do	Why it matters
Clean Up	Buy a broom, sweep three dirt piles	Introduces object interaction
Fixer Upper	Repair broken walls	Introduces the Scrap economy
Break & Build	Smash objects and craft two constructs	Introduces the mallet and blueprints
Explore the Deep Layers	Complete a first descent	Opens the run loop proper

The artifact economy is introduced in the same stretch. Murch hands you artifact coins, the gumball machine rolls them, and the opener turns the result into a construct blueprint you can build anywhere. The community route advice is not to chase every blueprint immediately: early on, bringing home enough Scrap to solve a real blocker is worth more than another random furniture unlock.

• Finish the housekeeping chain before farming; nothing later appears until it is done.
• Return to the Outpost and spend between dives instead of staying underground.
• Treat each descent as having one purpose: Scrap, Gold, a quest item, or a new route.
• Buy the solution to the current blocker, not every item that might become useful later.

Deep Layers Runs and Extraction

The Deep Layers are procedural, so the walkthrough is about habits rather than a fixed map. Treat the elevator as your anchor: leave it, clear one connected branch, then return to something you recognise before deciding whether another branch is worth the risk. Reading the elevator panel first tells you what the layer will throw at you, and the Broken Fuse modifier in particular adds an exit condition you should solve early rather than at the last minute. Community guides recommend preparing the extraction before you actually want to leave, because once the exit is ready, everything beyond your objective becomes optional risk.

Step	What to do	Why it matters
Read the panel	Check the elevator symbols before committing	Some rolls add an exit condition or extra enemies
Clear one branch	Work outward from the elevator, then return	Keeps you from losing the anchor
Process valuables	Feed sparkling objects to the Grinder or Compactor	Turns loot into Gold for the fare and upgrades
Prepare the exit	Pay the fare and solve fuse conditions while healthy	Prevents a last-minute collapse

The three rules that come up in every credited guide:

• Anchor on the elevator, because remembering one fixed map is not possible.
• Prepare extraction while the run is still healthy, not when health is nearly gone.
• Once you are carrying a progression item, protect it and take the safest route home.
• Reset to floor one when searching for a key, because easy layers are not a penalty.

The Rescue Quest, the Key, the Elite and the Surface

The first story gate is Little Buddy, the rescue quest. Biggy asks you to bring back a friend, and the credited guides say she spawns from around layer three onward, in a room close to the elevator rather than deep in the map. Circle the elevator left or right and you will find her. She has 250 HP, restores both her own health and yours, and follows you, so the safe pattern is to park your vessel in the elevator, go out as a Spark, collect her, and lead her back. The step teams get wrong is extracting alone, because she has to ride the elevator up with you for the quest to complete.

Objective	Where to look	The trap
Little Buddy rescue	Layer three or deeper, circling the elevator	Extracting without her onboard
Second Floor Key	Alcove near the elevator, any layer	Assuming it needs a deep floor
Tink and the Upgrader	Second floor after reopening	Boosting a weapon you will not keep
Corrupted Elite	Unmarked encounter room	Forcing it before the run is stable
Dr. Quill's records	Radio tower base hatch, Ancient Facility	Walking to the objective without accepting the quest

The Second Floor Key follows, and it is more forgiving: it can appear on any layer from floor one upward, so reset to floor one and search easy ground, watching for the alcove marked by a box, a light, a table, and a plant. Reopening the floor adds Tink, the equipment Upgrader, new upstairs rooms, and the balcony umbrella. The Elite objective that follows is the game's next combat checkpoint, with a charge attack you bait and punish, and after that progression moves topside to Dr. Quill's records quest, where a ground hatch at the radio tower's base leads to the Ancient Facility and its ten records.

• Do not search for the key on deep layers when floor one works.
• Bring the umbrella for the surface, because sunlight burns wooden vessels.
• Accept Dr. Quill's quest in his basement before walking to the objective.
• Recheck the access floor after each patch, since the credited wiki notes patches 1.01 to 1.07 did not move these steps.

The quests page breaks that chain down step by step, and the symbols page explains every elevator modifier you will meet on the way down.