According to my understanding, Buddha is all-aware. Just because he didn't stated directly all 112 methods of attaing enlightenment (Vijñāna Bhairava Tantra), that doesn't mean he was not aware of them. Gautama Buddha formulated his teachings with the aim of ending all suffering in human being. Appart from his teachings, we was aware of many other things as well:

Once the Blessed One was staying at Kosambi in the simsapa forest. Then, picking up a few simsapa leaves with his hand, he asked the monks, "What do you think, monks: Which are more numerous, the few simsapa leaves in my hand or those overhead in the simsapa forest?"

"The leaves in the hand of the Blessed One are few in number, lord. Those overhead in the simsapa forest are more numerous."

"In the same way, monks, those things that I have known with direct knowledge but have not taught are far more numerous [than what I have taught]. And why haven't I taught them? Because they are not connected with the goal, do not relate to the rudiments of the holy life, and do not lead to disenchantment, to dispassion, to cessation, to calm, to direct knowledge, to self-awakening, to Unbinding. That is why I have not taught them.

"And what have I taught? 'This is stress... This is the origination of stress... This is the cessation of stress... This is the path of practice leading to the cessation of stress': This is what I have taught. And why have I taught these things? Because they are connected with the goal, relate to the rudiments of the holy life, and lead to disenchantment, to dispassion, to cessation, to calm, to direct knowledge, to self-awakening, to Unbinding. This is why I have taught them.

"Therefore your duty is the contemplation, 'This is stress... This is the origination of stress... This is the cessation of stress.' Your duty is the contemplation, 'This is the path of practice leading to the cessation of stress.'"

-- Simsapa Sutta: The Simsapa Leaves

I have heard there are about 80,000 methods or ways of attaining Nibbana.

The Buddhist path has 3 elements:

1. Morality
2. Monastery over the mind
3. Wisdom

This method will take you to step 2 but not beyond. But again what you gain will not be the right type of Samadhi as you are not free from Vipallasa. Some practices here reenforce that soul is consciousness. At this stage, you will have to switch Vipassana.

Since this only takes you 2/3 of the way, with respect to the 8 fold path, at the most, even much less considering Release/Liberation itself, with the possibility of going astray, due to the lack of right view; so it is best you start with the Buddhist practice from day 1. Though the Path of Siva is not totally useless and misguided it is inferior to the Buddhist path, as Buddha learned all these techniques and beforehand and found a better path, leading to true liberation. Hence, the 8 fold path is what merits practice over the path of Siva.

The claim that the Buddha's way is part of the path of Siva is wrong as Buddhism is completely different in every aspect of morality, concentration and wisdom. Path of Siva takes up to concentration but not beyond. This too is not perfect. Path of Siva is not complete like the 8 fold path on all aspects of morality, concentration and wisdom, while wisdom being totally lacking.

NB: In Buddhism enlightenment is Release or liberation arising due to Wisdom, in Hinduism it is Samādhi. Buddhism also has Samādhi but takes a couple of steps further with Wisdom and Release. See: The Tenfold Path, From the Eightfold Path to the Tenfold Path and Ashtanga (eight limbs of yoga). The Buddha rejected the fact that deepest Samadhi is liberation and found that liberation is beyond which is Wisdom and Release. You can have Samadhi without a perfect Right View (Samadhi does not arise if you do not have some form of conducive view, through not Right View, which suspends the 5 Hindrances) but you cannot have Wisdom and Release without the Right View.

Buddha explicitly said that the only way to attain enlightenment is following the Noble Eightfold path. However, the way you enter Nibbana may have many doors. Hinduism doe not fitting to any of these as they do not have Noble Eightfold Path.

Eleven doors. Dasama Sutta.

When this was said, Dasama the householder from Atthakanagara said to Ven. Ananda, "Venerable Ananda, just as if a man seeking a single opening onto treasure were all at once to come upon eleven openings onto treasure, in the same way I — seeking a single doorway to the Deathless — have all at once come to hear of eleven doorways to the Deathless. And just as if a man whose house had eleven doors could take himself to safety by means of any one of those doors, in the same way I can take myself to safety by means of any one of these eleven doors to the Deathless. Venerable sir, when sectarians search for a teacher's fee for their teachers, why shouldn't I pay homage to Ven. Ananda?"

https://www.accesstoinsight.org/tipitaka/an/an11/an11.017.than.html

Hinduism's Lord Shiva found 112 ways to enlightenment.

The Buddha found 1 way to enlightenment.

Isaac Newton had his enlightenment when an apple fell on his head.

But all these types of enlightenment are not the same enlightenment. Hinduism's enlightenment and the Buddha's enlightenment are not the same.

The reason for this can be found in Indology Professor Helmuth von Glasenapp's comment in his essay Vedanta and Buddhism: A Comparative Study:

Nothing shows better the great distance that separates the Vedanta and the teachings of the Buddha, than the fact that the two principal concepts of Upanishadic wisdom, Atman and Brahman, do not appear anywhere in the Buddhist texts, with the clear and distinct meaning of a "primordial ground of the world, core of existence, ens realissimum (true substance)," or similarly.

yes he makes the usual mistakes of the puthujjanas infatuated with samadhi.

the idea of a small self is not the one of the buddha. This idea of small self is really the usual mistake of the brahmins and ascetics who managed to be skilled at some wrong samadhi and try to pass that as nibanna. They are forced to acknowledged that 5 usual senses have nothing to do with self, because ''the senses disappear'' with the jhanas, but they still invent some weird self from samadhi. This infatuation prevents them to see that vinnana is conditioned too. then they go to the buddha and whine that even though they are skilled at the jhanas, they have not seen the end of the world.

The lines about the sound are worthless. More generally, the lines with focusing on some objects to get into samadhi. This is the classical mistake even made today by people who call themselves buddhists, like the people infatuated with the Visuddhimagga.

for instance he says

“104. Wherever your attention alights, at this very point, experience.”

this is exactly the opposite of what the buddha says with sati sampajanna and a the big mistake people do today. They confuse tracking vedana-sanna-vitakka with nibanna, because they read that arhants are good at tracking those, so it means when a puthujjanas is good at tracking those, the puthujjana is an arhant.

Those people fail to understand that they need to filter vitakkas, filter sanna and vedana. And the first step is with vitakka, which will make the sanna-vedana good, ie with piti and sukha, and then there is right samadhi. But puthujjanas are too infatuated with their ideas to even think that ideas need to be sorted out.

People who just track those love to say that ''doing nothing'' is samadhi, but it is just worthless. THey do not understand that puthujjanas needs to purify what they experience. They do not understand that a puthujjana ''can have the mind of the buddha'', like people who invented mahayana say, while still being a puthujjana.

THe best that puthujjanas can come up with, on their won, is the non-ill will thoughts as good thoughts, but puthujjanas never ever think about the Nekkhamma, whereas it is really the thoughts of Nekkhamma, or more generally (in order to include even whatever happens in samadhi), dispassion, detachment, effacement, and so on which makes you progress. In fact, the whole path is based on this theme

There are, bhikkhus, these four knots. Which four? The bodily knot of craving, the bodily knot of ill-will, the bodily knot of attachment to religious rites, the bodily knot of holding on to 'This is the truth'. These, bhikkhus, are the four knots. For the direct knowledge of these four knots, bhikkhus, the five strengths should be developed. Which five?

Here, bhikkhus, a bhikkhu develops the strength of conviction, founded on seclusion, founded on disenchantment, founded on cessation, resulting in detachment; he develops the strength of exertion, founded on seclusion, founded on disenchantment, founded on cessation, resulting in detachment; he develops the strength of mindfulness, founded on seclusion, founded on disenchantment, founded on cessation, resulting in detachment; he develops the strength of concentration, founded on seclusion, founded on disenchantment, founded on cessation, resulting in detachment; he develops the strength of discernment, founded on seclusion, founded on disenchantment, founded on cessation, resulting in detachment.

http://www.buddha-vacana.org/sutta/samyutta/maha/sn50-102.html

THe puthujjanas who managed to think that thoughts of good will are good thoughts end up still being infatuated with that and the they come up with the wrong view that ''dukkha comes from not accepting everything'' and that ''nibanna is love'' and son. Those people never ever progress on the path because they lack half of the good thoughts and they are too infatuated with their wrong view to even try to base their life, what they do on seclusion, founded on disenchantment, founded on cessation, resulting in detachment.

THe whole point of the buddha is that right samadhi is reached with right thoughts, not by of focusing on a sound or visual object. When you do that you get wrong samadhi at best. Even with anapassati, the job is not to track breath but to calm whatever Sankhara you manage to be sensitive to, which all Sankharas normally, then to destroy them.

The problem of this list is that it is really general and lack too much details to base your life on it.

In searching for those lines, you see them printed on the book Zen Flesh, Zen Bones: A Collection of Zen and Pre-Zen Writings

https://books.google.com/books?id=u5dIDwAAQBAJ&pg=PT178&lpg=PT178

here is the preface of the section dedicated to the infatuation of the zen people towards this wrong view.

Zen is nothing new, neither is it anything old. Long before Buddha was born the search was on in India, as the present work shows.

Long after man has forgotten such words as Zen and Buddha, satori and koan, China and Japan and America—still the search will go on, still Zen will be seen even in flower, and grass-blade, before the sun.

The following is adapted from the preface to the first version in English of this ancient work.

Wandering in the ineffable beauty of Kashmir, above Srinagar I come upon the hermitage of Lakshmanjoo.

It overlooks green rice fields, the garden, of Shalimar and Nishat Bagh, lakes fringed with lotus. Water streams down from a mountaintop.

Here Lakshmanjoo—tall, full bodied, shining—welcomes me. He shares with me this ancient teaching from the Vigyan Bhairava and Sochanda Tantra, both written about four thousand years ago, and from Malini Vijaya Tantra, probably another thousand years older yet. It is an ancient teaching, copied and recopied countless times, and from it Lakshmanjoo has made the beginning of an English version. I transcribe it eleven more times to get it into the form given here.

Shiva first chanted it to his consort Devi in a language of love we have yet to learn. It is about the Immanent experience. It presents 112 ways to open the invisible door of consciousness. I see Lakshmanjoo gives his life to its practicing.

Some of the ways may appear redundant, yet each differs from any other. Some may seem simple, yet any one requires constant dedication even to test it.

Machines, ledgers, dancers, athletes balance. Just as centering or balance augments various skills, so it may awareness. As an experiment, try standing equally on both feet; then imagine you are shifting your balance slightly from foot to foot: just as balance centers, do you.

If we are conscious in part, this implies more inclusive consciousness. Have you a hand? Yes. That you know without doubt. But until asked the question were you cognizant of the hand apart?

Surely men as inspiritors, known and unknown to the world, have shared a common uncommon discovery. The Tao of Lao-tse, Nirvana of Buddha, Jehovah of Moses, the Father of Jesus, the Allah of Mohammed — all point to the experience.

No-thing-ness, spirit—once touched, the whole life clears.

no wonder people who invented zen completely fail to reach nibanna and are not even at the beginning of the noble path.