Пусть этот фильм и длинный, мне всё равно хочется посмотреть его снова.

In many sentences, пусть does mean let or may, as in Пусть он войдёт = Let him come in.

But in this sentence, пусть is being used differently: it introduces a concession. In the pattern пусть ... и ..., it means something like:

• even if
• even though
• granted that

So:

Пусть этот фильм и длинный...
means roughly: Even though this film is long...

This is a fairly common literary or neutral written/spoken way to acknowledge one fact and then contrast it with another.

Right — here и is not the normal and.

In the structure пусть ... и ..., the и helps create the meaning of concession:

• Пусть он и молод, но опытен.
  Even though he is young, he is experienced.

• Пусть фильм и длинный, мне хочется посмотреть его снова.
  Even though the film is long, I want to watch it again.

So и is part of the pattern, not a separate and joining two equal items.

You can think of пусть X и Y as a set expression meaning granted that X is Y / even though X is Y.

Длинный is the normal full-form adjective, and in modern Russian it is very natural here.

Russian usually does not use есть as a present-tense copula in sentences like the film is long. So:

• Этот фильм длинный. = This film is long.

There is no need for есть.

As for длинен, that is the short-form adjective. Short forms do exist, but they are often more formal, literary, or limited in usage depending on the adjective. For everyday Russian, длинный is the most natural choice here.

So:

• Этот фильм длинный = normal, natural
• Этот фильм длинен = possible, but less ordinary in everyday speech

Because the sentence uses хочется, which is an impersonal construction.

Russian often expresses feelings or involuntary states this way:

• мне хочется = I feel like / I want
• literally something like to me, it is wanted

So the person experiencing the feeling goes in the dative case:

• мне хочется = I want / I feel like
• тебе хочется = you want / you feel like
• ему хочется = he wants / he feels like

That is why we get:

мне всё равно хочется посмотреть его снова
= I still want to watch it again

not я хочется, which would be ungrammatical.

Both can relate to wanting, but they are not exactly the same.

я хочу

This is more direct and personal:

• Я хочу посмотреть фильм.
  I want to watch the film.

мне хочется

This often sounds softer, more like:

• I feel like
• I’m in the mood to
• I still have the desire to

So in this sentence, мне всё равно хочется has a natural emotional tone: despite the film being long, the speaker still feels like watching it again.

Compare:

• Я всё равно хочу посмотреть его снова.
  More direct: I still want to watch it again.

• Мне всё равно хочется посмотреть его снова.
  Slightly softer, more about the feeling/desire arising in the speaker.

Both are possible, but хочется fits the tone nicely.

Here всё равно means:

• all the same
• anyway
• still
• nevertheless

So:

мне всё равно хочется посмотреть его снова
= I still want to watch it again / I want to watch it again anyway

It shows that the second part remains true despite the first part:

• The film is long.
• Even so, I still want to watch it again.

A very common phrase in Russian.

Because посмотреть is the perfective form, and here it presents the action as a complete event: to watch the film once, from beginning to end.

• смотреть = imperfective, process, habit, repeated activity
• посмотреть = perfective, one complete viewing

So:

хочется посмотреть его снова
means I feel like watching it again (one more time, as a complete viewing)

If you used смотреть, it would sound more like focusing on the process or activity itself, and in this sentence посмотреть is the more natural choice.

Его here means it, referring to фильм.

Russian object pronouns do not always visibly distinguish gender and case the way English does. For masculine/neuter singular in the accusative, его is the normal form for him/it, depending on context.

So:

• посмотреть фильм = watch the film
• посмотреть его = watch it

Because фильм is masculine, его refers back to it naturally.

Even though его can also mean his or him, the context here makes it clearly it.

You could repeat it, but его is more natural and less repetitive.

Compare:

• ...хочется посмотреть этот фильм снова
• ...хочется посмотреть его снова

Both are possible, but Russian, like English, often prefers a pronoun once the noun has already been mentioned.

So его simply avoids unnecessary repetition.

Yes, снова is flexible.

In this sentence:

мне всё равно хочется посмотреть его снова

снова at the end is very natural and clearly means again.

You could also hear:

• мне всё равно хочется снова посмотреть его
• мне всё равно хочется посмотреть снова этот фильм
  (less natural here)

The end position is smooth and common. It puts the idea of again in a slightly prominent spot.

So the chosen word order is natural, but not the only possible one.

Yes, exactly.

A very close breakdown is:

• Пусть этот фильм и длинный = Even though this film is long
• мне всё равно хочется = I still feel like / I still want
• посмотреть его снова = watching it again

So the full sense is:

Even though this film is long, I still want to watch it again.

The Russian has a slightly natural, nuanced feel: the speaker acknowledges a possible objection (it’s long) but says that this does not change their desire.

It is mostly neutral, but the concessive pattern пусть ... и ... can sound a little more polished or bookish than the most casual everyday speech.

A more conversational alternative might be:

• Хотя этот фильм длинный, мне всё равно хочется посмотреть его снова.

That means almost the same thing:

Although this film is long, I still want to watch it again.

So the original sentence is perfectly natural, but it has a slightly more stylistically marked structure than the very common хотя version.