I've tried to rig this up so that you won't get spoilers unless you go looking for them -- I really hope you let yourself play the game, because it's a lot of fun.

One note: if you're going for all the achievements, it's a good idea to keep a couple different save files along the way, because it *IS* possible to save/lock yourself out of a couple achievements if you miss some things and then save after, and if you don't have a backup, you'll need to play through again.

• I've compiled screenshots into composite maps, using a Google Sheet.
  
• You do not need a google account to view the sheets.
• If you do have a google account, you can open the sheets in an incognito or private window (or just log out) to avoid viewing the sheets from your account.
  
• The Landing page[docs.google.com] will provide some additional info. Tabs at the bottom take you to the maps.

Here's the full link if you want to copy-paste it:
I'll admit this way of doing things is a little awkward, but using a sheet to store/arrange the images seemed like a decent option. Let me know in the comments if you find it really clunky or if it's acceptable.

Detailed walkthroughs/spoilers are in the maps. If you don't want them, you can just ignore all this, and just use the maps to help orient yourself.

• Click or hover on screens/cells in the map to reveal a pop-up note containing spoilers about that screen/cell.
  
• In addition, at the top-left corner of most maps, a pop-up offers a rough walkthrough of where to go and in what order.
  
• Clicking or hovering a screen/cell usually won't immediately reveal an extreme spoiler: you still need to scroll through the pop-up.
• I've tried to offer different "levels" of hint/spoilers: if you don't scroll all the way through the pop-up, you just get a tiny hint. If you scroll all the way to the bottom, things get very explicit.

BUT!
Google Sheets is a little dumb in how it handles hover-notes in cells. If you scroll all the way down in 1 note, the Sheet will "remember" that you scrolled all the way down, and the 2nd note you open will inherit the scroll. So, if you want to avoid spoilers, always scroll back up after reading a note.

Only a couple achievements will unlock naturally as you complete the story -- and technically, even #7 below is missable if you don't continue on past the first ending...

Most achievements are missable, and some have dependencies on others. I list them in the rough order in which you could unlock them -- which doesn't correspond to the Trophy # shown in your inventory once you get them. (You can check your inventory to see which ones you're missing). Only the first achievement below can be unlocked early in the game. Most of them can be unlocked later even if you missed something earlier, AS LONG AS YOU HAVE A SAVE TO LOAD FROM and don't mind doing some backtracking.

You can enter the mines from 3 different locations using secret entrances/exits near the screen's edge. Below, behind spoilers, I'll list which screens go to the mines, and give links to them in my map (you might need to scroll to find the cell).

1. Ancient Being's lake -- Cell C10[docs.google.com]
   
2. Outside the maze -- Cell E16[docs.google.com]
   
3. Outside the Castle -- Cell E4[docs.google.com]

This is complicated, and you can't get it til late game. As long as you haven't left Monster Island you can still get it. Spoilers below:

1. Get to Monster Island
2. Make your way through the Mountain Caves
3. Before escaping Maporia Village, use bombs to uncover a secret path through the mountains. Explicit info, is on my Monster Island map, in Cell 06[docs.google.com]
4. Get the birdseed, then find a bird to give it to.... if you want explicit info, see Cell i15[docs.google.com]

There's a new spot you can access after you defeat the desert god, and before you return the Main Island. You've probably already seen it before, but if you want a reminder, it's: Cell D21[docs.google.com]

Lore is scattered in notes around both islands. As a rule: interact with everything you can. Specific info below. This may not be a complete list (and these may not all be necessary), so please let me know if you spot something I missed here. The only one you may need to do early in the game (before you get a mushroom) is #1. You should be able to backtrack to all others.

ON MAIN ISLAND:
1. Read the note in the tent outside Grandpa's house: Cell C15[docs.google.com]
   
2. Read all lone gravestones, and examine the lone rock near 1 gravestone: Cells E10[docs.google.com] and G13[docs.google.com]
   
3. Read the books in the library: Cell D8[docs.google.com]
   NOT ON MAIN ISLAND:
   
4. Read all notes in Water Palace Library: Cell F9[docs.google.com]
   
5. Read all notes in tents in Maporia Village: Lots of Cells near M4[docs.google.com]
   
6. Read the note in the hut on the Secret Island: Cell B16[docs.google.com]

These are scattered on both islands. The only one you need to do early (before you get a mushroom) is #1. You should be able to backtrack to all others. This may not be a complete list (and these may not all be necessary) so let me know if you spot something I missed here.

ON MAIN ISLAND
1. Examine all the stuff upstairs in Grandpa's house
   
2. Try entering the shack next to Grandpa's house -- Cell B15[docs.google.com]
   
3. Examine all gravestones in the main cemetary-- Cell F13[docs.google.com]
   
4. Dive in the Drowning Pond with Fins and get to the chest -- Cell C11[docs.google.com]
   
5. Talk to the person inside the shack (continue from #4 above)
   NOT ON MAIN ISLAND
   
6. Read the note on the cave wall in Maporia Village -- Cell M4[docs.google.com]

You can only get this after you've returned to the Main Island after a long detour. Spoilers below:

1. Defeat the desert god, then return to the Main Island
   
2. Go to the secret cave behind the waterfall. You can now enter it -- Cell B13[docs.google.com]

Pretty much says it all. Whenever you get the last trophy you're missing, you should get this too.
NOTE: You don't actually get this for having ALL the achievements...

The trick here is that when you enter the cave to get the "True Ending," you can leave. If you've gotten everything else, you'll have all 9 trophies. Inexplicably, things will now be a little different if you return to the mines and check out the bottomless pit...