Learn Hardcore Russian: Сегодня мне совсем не работается, зато очень хочется посмотреть фильм. - Today I can’t work at all, but I really feel like watching a movie.

Dative case = the experiencer (the person who feels it) → мне = to me / for me
Verb in 3rd person singular, often with -ся → работается

So мне не работается is literally something like:
“It doesn’t work itself (for) me” → naturally: “I don’t feel like working / I can’t get any work done.”

We do not say я here, because the structure is not “I work”, but “(It) doesn’t work (for me).”

What exactly does работается mean, and how is it different from работать?

работать = to work (neutral, basic verb)
- Я работаю. – I am working.
работаться (impersonal, with -ся) often means something like
- to get done easily, to go well as work, to feel like working.

Typical patterns:

Мне сегодня хорошо работается. – Today I’m working well / work is going smoothly for me.
Мне совсем не работается. – I really don’t feel like working at all / I can’t work at all (nothing is getting done).

So работается is more about how the work process feels or goes, not just the bare fact that you are or aren’t working.

Why do we say совсем не работается instead of just не работается?

совсем strengthens the negation:

не работается – it doesn’t work / I don’t feel like working.
совсем не работается – I don’t feel like working at all, absolutely can’t work, really not working.

Other examples:

Я совсем не понимаю. – I don’t understand at all.
Он совсем не устал. – He’s not tired at all.

So совсем makes the sentence more emphatic and emotional: you’re really not in a working mood.

What is the difference between хочется and хочу?

Both come from the idea “to want”, but they are used differently:

хочу (from хотеть) – personal form
- Needs a subject in the nominative: я, ты, он…
- Я хочу посмотреть фильм. – I want to watch a movie.
хочется (from хотеться) – impersonal form with -ся
- Usually used with dative: мне, тебе, ему…
- Мне хочется посмотреть фильм. – I feel like watching a movie.

Nuance:

хочу sounds more direct, “I want (this)”.
хочется is softer, more about a spontaneous desire or mood: “I feel like (it)” rather than a firm, deliberate wish.

In your sentence, очень хочется посмотреть фильм = I really feel like watching a film.

Why is мне only said once? Why not Сегодня мне совсем не работается, зато мне очень хочется посмотреть фильм?

You can repeat мне, but it’s not required.

In Сегодня мне совсем не работается, зато очень хочется посмотреть фильм, the dative мне naturally “extends” over the second part. The listener understands that хочется refers to the same person.
Adding мне again (…зато мне очень хочется…) is also correct; it just sounds slightly more explicit, with a bit more emphasis on “but for me, on the other hand, I really feel like…”.

Both versions are grammatical. The original sentence is just a bit lighter and more natural in everyday speech.

Why is it посмотреть фильм and not смотреть фильм?

This is about aspect:

смотреть – imperfective: focuses on the process (to be watching, to watch in general).
посмотреть – perfective: focuses on a single, complete action (to watch something once, from start to finish).

In the sentence, хочется посмотреть фильм expresses the desire to watch a whole film (once), as a complete activity. That’s why perfective посмотреть is natural.

Compare:

Я люблю смотреть фильмы. – I like watching films (in general).
Я хочу посмотреть фильм. – I want to watch a film (one specific viewing, from beginning to end).

What does зато mean here, and how is it different from но?

Both зато and но can be translated as “but”, but they have different nuances:

но – a neutral “but”, simply contrasts two things.
зато – “but on the other hand”, often with a feeling of compensation.

In the sentence:

Сегодня мне совсем не работается, зато очень хочется посмотреть фильм.

The idea is:

Today I really can’t get any work done, *but (on the other hand) I really feel like watching a movie.*

So зато implies: okay, this negative thing (no work), but there is a “compensating” positive thing (a movie) instead.

Why is there no я in the sentence? Is it normal to leave out the subject like that?

Yes, this is completely normal in Russian, because:

The verbs работается and хочется are used impersonally (no grammatical subject).
The experiencer is shown by the dative: мне.

So the structure is not “I work / I want”, but:

(It) does not work (for me) – мне не работается
(It) very much is wanted (for me) to watch a film – мне очень хочется посмотреть фильм

Russian often uses such impersonal constructions to talk about states, feelings, and weather:

Мне холодно. – I’m cold. (literally It is cold to me.)
Мне грустно. – I’m sad.
Мне не спится. – I can’t sleep / I don’t feel like sleeping.

So no я is needed or natural here.

Can I rewrite this with more “normal” personal verbs like я не хочу работать? How would it sound?

You can, for example:

Сегодня я совсем не хочу работать, зато очень хочу посмотреть фильм.

This is perfectly correct and means roughly the same:
“Today I really don’t want to work at all, but I really want to watch a movie.”

Nuance difference:

мне не работается / мне хочется – more about inner mood / state, softer and a bit more colloquial or emotional.
я не хочу / я хочу – more direct, like you are stating a clear will or decision.

The original with мне не работается… хочется… sounds very natural in spoken Russian when talking about your mood.

What case is фильм in, and why is there no preposition?

фильм here is in the accusative case as the direct object of посмотреть:

Nominative (dictionary form): фильм
Accusative (masculine, inanimate): also фильм (same form)

Russian doesn’t use a preposition like English “watch *a film”* – you just put the noun directly after the verb:

смотреть фильм – to watch a film
читать книгу – to read a book
есть яблоко – to eat an apple

So посмотреть фильм is simply “to watch a film” with фильм as a direct object in the accusative.