First, assuming you're fresh into the game, SUPER basic info:

• The green number shows how much of the item you picked up is in your inventory, and the yellow number is how much damage you're doing to something. Orange is just that but for zombies, and red is how much damage you're taking.

• The version doesn't really matter; P.Craft, P.Craft Deluxe, and Stranded Isle have the same Any%. See the guide on versions for more info.

• You beat the game by placing a boat and leaving the island. Timing begins on first input in a new world, and ends either on save disc's first frame of appearance, or the victory screen, for Deluxe/SI and P.Craft respectively.

From here, it's a basic Any% guide. I recommend only following this verbatim if you're new, and I'll explain why later:

1 - Get 5 wood by punching trees. You can count to 8 and avoid the slowness effect that happens when you punch too much, by the way.

2 - Place your wooden table and craft a wooden pickaxe.

3 - Get 20 stone, use the wooden table to make a stone table, and use that to make a stone pick.

4 - Things start to diverge here across runs, but for now, I recommend getting 19 stone here.

5 - Make a stone sword, axe, and shovel. I recommend picking up your benches here as well.

6 - Use your axe to get 65 wood, and switch to your sword to kill zombies along the way. Again, different runs do different things, but for this guide let's go wood first.

7 - Head down to cave, and start mining for the following materials: 10 gem, 24 iron, 30 stone. If there's any zombies, kill them.

8 - Shovel up 36 sand, and go back to the surface.

9 - A few zombies from before have hopefully netted you ~7 ichor and some fabric. Now all you need is 27 ichor and 12 fabric total, so kill a bunch of zombies for that. If you can't find any, zombies respawn every time you go down or up the ladder, so just keep doing that until you have all of the stuff you need.

10 - Now is the time to do "end menuing," which basically has you craft everything you just collected into a boat or something that makes a boat. It goes like this:

• Place down both wooden table and stone table.
• Go into the stone table, make a furnace, and place it.
• Make 8 iron bars and 12 glass.
• Go to the wooden table, and make a chem table and factory. Place the chem table.
• Make 9 glue.
• Place the factory.
• Make 4 sails, then a boat.

11 - Now that end menuing is finished and you have a boat, place it in any tile of water. It doesn't matter whether it's in a cave, in a puddle, etc.

Using this exact route, you're likely able to get a respectable time. You can improve relatively quickly with a few other things in the back of your mind, though:

A. The entire game is heavily RNG-dependent when doing a run. Every single drop in the game has a chance to be one thing and a chance to be another thing, ex. trees, stone, and ores drop 2-4 at random. (Not if it's in Any% w/ perfect drops, a.k.a. Dream% (Any%), though. The following is still present, though.) Zombies will also spawn at random, and the map generation is almost entirely random, with only the stone around the ladder remaining the same. Even damage dealt is random between 2 values, ex. stone pickaxes go from 5 to 8. All of this to say, you can improve times by simply playing the game more.

B. The seed is VITAL to a good run. A perfect seed has the ladder in view, some trees, and at least a small bit of extra stone, as well as a lot of open area for zombies to spawn. (In my opinion anyway, top runners have a different definition of what is a "perfect" or even viable seed.) A little pond is also nice, but not necessary if water is at least somewhere close by. As long as a seed has some trees and close ladder/stone, though, it's runnable.

C. The route can be switched around with little consequence. It's mostly a judgement call what you do when after a stone pick, ex. getting all the cave stuff may be a lot easier than getting a lot of trees to begin, so it's perfectly fine to start with that and/or move getting sand or stone to the surface for a faster and easier time. As long as you get stone tools before trying to get stuff like wood, it's almost required to break the structure of the route I laid out above to be consistently faster. Being able to mix things up and not stay rigid is the first mental barrier you gotta break when speedrunning SI, alongside multithreading and EBM whenever you move up a notch.

From here down, this is stuff I recommend familiars with SI read through to improve their times. I ordered it from generally the most vital to least vital tips for anyone looking to get better with everything above already known:

• Don't lock yourself into doing one thing at a time. Just like killing zombies whenever you can, you should spawn them as often as you can, and also be open to collecting multiple things at a time. For example, after depleting your bar from mining gemore, (gem ore) you may have time to go up the ladder and kill some zombies before going back down and finishing it off. Maybe you need to mine an iron ore or dig some sand along the way there to not lose time, and that's okay. It's optimal, even. This is called "Multithreading" and will massively help you improve your times.
• EBM, or Extended Bar Management, is just not letting your bar completely empty out or completely fill up, to summarize. Always be doing something, even if that means taking an indirect route. Ex, killing a zombie at the edge of the screen, where to keep EBM I break a tree or two on my way. Same applies in caves, too; if an ore is too far away, shovel some sand on your way there. That's an abridged version of applying EBM, anyway.
• All newly-collected items go to the bottom of your menu, and otherwise it's in the order you last used something. Keeping a mental map of your menu, therefore, is fairly easy to do, and can save you some time, especially when you have to switch between tools quite a bit. At least remember where your tables are, so that you can mash directly to them faster. If you didn't know, going up at the top of a menu will take you to the bottom as well, which makes fetching stuff like your stone tools faster.
• "Quick Placing," previously dubbed "Plenuing" and also called "Paul Placing," is basically a frame-perfect button press to place a table without losing stamina. Literally just press the place button 1 frame. Alternatively, whenever punching trees at the start, you can time placing the workbench while hitting a tree to do the 2-for-1 "Plunch," but it's a more niche use case than quick placing.

That's about it! I'll update this whenever either a newbie asks a question not answered here, or an experienced runner wants something added for newer players. Thank you for reading, and I hope you run SI!

(Make sure to look at Andrew's Boss Kill% guide, and keep an eye out for some Misc. category routes being put up in the future!)