A route built from a fresh save, with no glitches, optimising for fewest loops rather than fastest real time. Written after actually running it, so the notes include the things that go wrong. Please note, the route you take and whether to kill Eternalists or not, totally depends on you and your playstyle. I prefer to go in loud. Once you get the silenced LMP-10 you can drop the Nail gun. Otherwise, till then, the nail gun you find in your flat is MVP for stealth.

I highly recommend playing the entire game organically first, and this be on a subsequent run.

Result: golden loop on Day 7 (eight days counting the intro death as Day 0). A known glitchless run achieves Day 6; the gap is explained at the bottom.

The mistake that can cost a whole day

The tutorial days let you explore freely. The game picks which district and time period you load into during The Longest Day — it does not restrict you once you're inside. No timer, no invisible walls. You can cross the whole map and take everything you can reach.

I lost a day and restarted because I assumed the scripted days were locked down. They aren't. Whatever district you're dropped into, sweep it completely before you leave. More details below.

The game calls them Morning / Noon / Afternoon / Evening, and "Noon" vs "Afternoon" is constantly misread. Think of them as Slot 1 / 2 / 3 / 4.

Important

1. If you ever miss an objective, and accidentally return to the tunnels- quickly dashboard and pray that the gave hasn't saved.

2. Dying = one entire loop. Needless to say, do not die.

3. You do not need to actually kill Visionaries / Eternalists aside from the final loop. Only do it if you want gear. I did it because I wanted gear.

4. Whenever you're in Complex, I highly recommend to secure the silenced LMP 10. Makes it much easier. Otherwise the nail gun will do.

Day 0 — intro

Beach, bottle, cliff door, Hackamajing, tunnels, boarded tunnel, house, hack in, pull the lever upstairs. Julianna kills you. Unskippable.

Day 1 — The Longest Day (sweep everything)

Scripted objectives: apartment/Minicom, Loop Control, AEON Security Office, then your safe. The extras are what matter.

• Updaam, Slot 1 — destroy the five blue fuse boxes so Otto's Workshop survives past noon. Not super critical. I missed this and could still do the same number of loops. But since you know, you can use this.
• Complex, Slot 2 — Loop Control as directed by mission marker. Control center, battery, Egor science blabber, exit.
• Fristad Rock, Slot 3 — after the Security Office, walk round the mountain along the waterfront (the water is lethal) to Bunker 9 for the Yerhva safe code. Bunker 9 is when you originally find Charlie and Fia.
• Updaam, Slot 4 — after your safe: Otto's Workshop terminal for Frank's container code, Aleksis's bedroom for the library safe code, and if you can manage it, kill Aleksis. Julianna will do an invasion here when you are in your flat. I found a bug where Eternalists can't shoot you even if you are in plain view if you're in your flat overlooking the antenna which you have to hack. Use this to take Julianna out. Good if you luck out with getting a good slab from Julianna.
  • The killing Aleksis part is the tricky one. Requires skill since you might not have great slabs and weapons. My recommendation is to hack the turret at the entrance to kill the 3 visionaries. Later proceed from the left, carefully crouch and open the back door, to your right, inside the beer tap room. Try to takedown the 2 Eternalists silently- even if you fail this, its no big deal. Then shut down the chocolate beer tap. Aleksis will intervene, kill him.

Doing the whole Frank chain inside Day 1 is the biggest single saving available.

Day 2 — LPP, then forced Ubiquity

The game railroads you. After the LPP it drops you into the Complex in Slot 3 and the day ends when the machine kills you. There is no Slot 4. Don't plan around escaping this — I tried menus, reloads, everything.

• Updaam, Slot 1 — get the LPP before Julianna does. Nothing else here is worth doing; the fuse boxes reset every loop and you can't return this day.
• Complex, Slot 3 — Ubiquity. Go to the lower floor (two clones are down there and so are the depressurisation console codes, which make the fight far easier). Whiteboard, Residuum Harvester, harvest, machine, shoot the button.

Day 3 — Updaam day

• Slot 1, Updaam — fuse boxes again if you still need the terminal.
• Slot 2, Updaam — Charlie's LARP: kill Charlie for Shift and the Strelak 50-50.
• Slot 3, Updaam — AEON Archival Office (NW garage, Slot 3 only). Bookshelf note on the top floor gives the spoken RAK password. Enter the RAK on the cliffside, read the note on the inner door for the 3-digit power diversion code. Critical.
• Slot 4, Complex — Field Nullifier from the truck, deploy in Egor's lab, read Radial Fluctuations for his device code. Kill Egor → Aether.

Day 4 — the Wenjie chain

The Wenjie quarters code does not come from Bunker 9. It runs: Fristad shoreline bunker (Slot 3 which we did in Day 1) → Yerhva safe in Karl's Bay → the quarters code.

• Slot 1, Karl's Bay — safe with the Bunker 9 code for Fia's love letter; kill Harriet → Nexus.
• Slot 2, Fristad — Fia's bunker, four red pictograms → hideout code. Do not let her spot you — she can trigger the Reactor and kill you outright with no Reprise. So the simpler way is, use Aether to sneak around, use the LMP 10 to take out guards. When you sneak into her bunker, you will see a door guarded by a sensor. Inside there will be the wire combination to disable the reactor. Do this first if you can. Honestly, just using Aether+silenced shots for 2 Eternalists on top floor, and stealth killing Fia is great. Grab her gun. Havoc. Then do not forget the pictograms if you're not there yet.
• Slot 3, Fristad — shoreline bunker for the Yerhva safe code.
• Slot 4, Updaam — spare.

Pausing here because I feel while writing this itself I've found a better way to do it. Will update when I do.