Infinite Cave adventure: (Save a wolf, kill an Elder God)

Infinite Cave Adventure, or incavead for short is a very fast-paced game about retrieving "the ring of power" descending from dungeon to dungeon and taking it to the astral throne, deep in the bowels of the earth.
Sounds easy, right?
Wrong.
Your combat skills are non-existent. The best weapon you'll find on the surface before diving is a broken sword, with a broken shield as defence. Kobold pups and courtesans are going to tear you apart if you just try to attack them. The ring is found several dungeons deep in most cases, since it doesn't reset like every other item of the game, it's permanently in one place until someone finds it and brings it a little closer to level 15, where the astral throne can be found in all its glory.
Surprisingly, most people don't even find it and when they do, they get slaughtered by dark tendrils, angels or good ol' fashioned dragons.
So, why are we all playing this game again? Doesn't really seem like something a normal human being would play, it's not even a hack& slash, since attacking monsters is a quick way to the other world even in DL 1 and the difficulty grows exponentially. Yes, you are supposed to run away from monsters and not kill them, like any sane human being would do.
Did this introduction intrigue you? Then welcome to the world of

Infinite Cave adventure: (Save a wolf, kill an Elder God)

I'm not going to spoil everything for you, my little adventurer. Where's the fun in that? But I'm going to give you hints and actually explain some things so that you don't keep asking everything in the general. As always, remember to do "??" to get a very detailed, but spoilerless guide on the game.
Ready?

You spawn on the surface, at level 0. There are several things you could do now: Get some objects and dive, kill some rabbits for meat (you're not getting less hungry, you know) and try your skills with a wolf. I recommend the first two and strongly advise the third one for obvious reasons you'll see by yourself.
Hint: try to get a broken sword, but don't worry about shields for as long as you stay on the surface. Get one only if you stumble upon it or if you've decided you're going to start your journey.
Hint: Meat gives two + to your hunger bar and you can carry up to 5 pieces. Get them all before starting.
Hint: In the extremely unfortunate case you encounter a wolf, remember that these guys have very bad eyesight. They also don't like getting wet. You'll find out later what that means.

How to think with portals: Blue and yellow.
If you've stumbled upon a blue or a yellow tile that says "a column of shimmering light", interact with it. Yellow ones bring you to the moon (DL-1, which is said to possess some items that could aid the player in his quest. Will you find them?
Hint: remember, you're going UP, when you're supposed to go DOWN to get the ring. Don't stay too much on the moon and find a way to go back town on the earth. It might really be easier than you think.
Blue ones bring you to the realm of the wizards! (DL-3/-4) Like on the moon, there are several items that could help you in your journey, but beware.
Hint: Lunites are friendly if you stay out of their way, but wizards are a different thing entirely. Especially apprentices, they've still got good eyesight.
Hint: Some folks tell us of the mystical sanctuaries of the wizards... but only few have come back to tell the tale.
These men tell of shrines where simple branches can be turned into something incredibly powerful and dangerous.
Hint:What do you wish for?

Now that that is covered up, it's time we talk a little more about gravestones and sigils.
Gravestones. Everyone deserves one and everyone gets one. When you die, your death will always be remembered (and in the case of some greedy sods, thanked).
Hint: It is common belief that the spirits of the dead shroud whoever stays on the graves from any kind of wizardry.
Hint: Money. More than you can carry.

Sigils. And just what are these incredible forces? Some can create holes in existence itself, where the soul and body of the traveller are twisted and destroyed. Using these is a suicidal task left only to some deranged maniacs. Do not tread on their red remains.
Another, more regular kind of hole, not in existence but on the dungeon floor, can be made with the help of another sigil.
There is also a sigil that will let you create an impenetrable box which is told to be able to fit and preserve every object, but only one.
There are more obscure sigils, but I'll let you find them and understand their use, traveller. Remember that every one of them has its purpose and even the ones that seem useless can save your life in some dire situations.
Hint: Red is the colour of death.
Hint: Amber is the colour of the descent.
Hint: Blue is the colour of safekeeping.

Don't go around killing too many kobolds.
I personally wouldn't mind about achievements.
Running isn't always the best option if you've been spotted.
Always keep a portable hole in your inventory. Always.
Go kill some wizards.
The Matrix teaches you a lot about statues.
Don't wish for armor or shields or weapons.
Luck is actually very important if you're thinking of attacking someone or if you're running away from spellcasters.
Melee is bad for your health. Go ranged.
Take a closer look at the number you see when you die.
The ring can't be brought to the astral throne if you found it in a tunnel, because of a bug or an intended feature. It will need to be destroyed and regenerate on DL1. Do not take any tunnels if you have the ring.

That is all I will tell you, young hero. You will need to find your answers yourself, by trial and error.
Go forth and Godspeed. Say hi to the dark lord from me if you see him.

-Anon