Если тебе хочется что‑нибудь посмотреть, включи этот фильм.

Because хочется goes with the dative case.

Russian often expresses feelings like I feel like... with an impersonal structure:

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

So тебе means to you, not you as the subject.
The structure is roughly: If to you it feels desirable to watch something...

That sounds odd in English, but it is very natural in Russian.

Хочется comes from хотеться, which means to feel like doing something. It is often more impersonal and softer than хотеть.

Compare:

• Ты хочешь посмотреть фильм. = You want to watch a film.
• Тебе хочется посмотреть фильм. = You feel like watching a film.

So хочется often suggests a passing desire, mood, or urge, rather than a direct, firm intention.

In this sentence, тебе хочется sounds natural because the idea is if you’re in the mood to watch something.

In Russian, что‑нибудь is very common in conditional, question, and uncertain contexts.

Here the sentence begins with Если... (if...), so что‑нибудь fits very well:

• Если тебе хочется что‑нибудь посмотреть... = If you feel like watching anything / something...

A useful contrast:

• что-то = something (often some unspecified but more concrete thing)
• что‑нибудь = anything / something or other (more open-ended)

So after если and in similar situations, Russian often prefers -нибудь words.

Because -нибудь is a particle that attaches to pronouns and adverbs with a hyphen.

For example:

• кто‑нибудь = anyone / someone
• что‑нибудь = anything / something
• где‑нибудь = anywhere / somewhere

So the hyphen is just part of the normal spelling.

Because посмотреть is perfective, while смотреть is imperfective.

Here, посмотреть means something like to watch / have a look at as a complete action. In this sentence, the idea is:

• feel like watching something (one thing, as a complete viewing choice)

That is why посмотреть sounds natural.

Compare:

• смотреть = to watch, to be watching, to watch in general
• посмотреть = to watch / take a look / watch through once

With films, Russian very often uses посмотреть when talking about choosing and watching a movie.

Yes. Включи literally means turn on / switch on.

But with media like a film, show, video, or music, Russian often uses включить in the sense of:

• put on
• play
• turn on

So:

• включи этот фильм = put this film on / turn this film on

This is very natural Russian.

Yes. Включи is the singular informal imperative.

So this sentence is addressed to:

• one person
• someone you say ты to

Polite or plural would be:

• Если вам хочется что‑нибудь посмотреть, включите этот фильм.

So:

• включи = informal singular
• включите = polite singular or plural

Because фильм is masculine inanimate, and in Russian the accusative singular of masculine inanimate nouns is the same as the nominative singular.

So:

• nominative: этот фильм
• accusative: этот фильм

That is why the form does not change here, even though этот фильм is the object of включи.

If it were animate, the accusative would usually look like the genitive instead.

Because Если тебе хочется что‑нибудь посмотреть is a subordinate clause introduced by если (if).

Russian normally puts a comma between the if-clause and the main clause:

• Если ..., ...

So:

• Если тебе хочется что‑нибудь посмотреть, включи этот фильм.

This is standard punctuation.

Yes, you can.

That version uses хочешь instead of хочется:

• Если ты хочешь... = If you want...
• Если тебе хочется... = If you feel like...

Both are correct, but the nuance is slightly different:

• хочешь = more direct, straightforward
• хочется = more about mood or desire at the moment

In a recommendation like this, тебе хочется often sounds a bit softer and more natural.

Yes. Russian word order is fairly flexible.

The neutral order here is:

• Если тебе хочется что‑нибудь посмотреть, включи этот фильм.

But other orders are possible for emphasis, for example:

• Если тебе хочется посмотреть что‑нибудь, включи этот фильм.

That also works. The meaning is basically the same, though the rhythm and emphasis shift slightly.

In general, Russian word order often changes to highlight different parts of the sentence, even when the basic meaning stays the same.