Мне понравился финал этого спектакля.

Because Russian expresses to like differently from English.

In Мне понравился финал этого спектакля, the person who experiences the feeling goes in the dative case:

• мне = to me

The thing that caused the feeling is the grammatical subject:

• финал = the ending

So the structure is closer to:

• The ending of this play pleased me
• literally: To me, the ending of this play was pleasing

That is why я понравился would not mean I liked. It would mean someone liked me or I was pleasing/appealing.

Because it agrees with финал, which is:

• masculine
• singular
• nominative

In the past tense, Russian verbs often agree with the subject in gender and number:

• финал понравился — masculine singular
• книга понравилась — feminine singular
• письмо понравилось — neuter singular
• книги понравились — plural

So понравился is masculine because финал is masculine.

Because финал is the grammatical subject of the sentence.

Even though English says I liked the ending, Russian structures it more like:

• The ending pleased me

So:

• мне = dative experiencer
• финал = nominative subject

That is why you get:

• Мне понравился финал not
• Мне понравился финала

This is a very common question because it involves aspect.

• нравиться = imperfective
• понравиться = perfective

In this sentence, понравился suggests a completed reaction or overall impression:

• I liked the ending
• The ending appealed to me

It often fits well when talking about a specific event, performance, film, book, scene, and so on.

By contrast, нравился would usually describe an ongoing, repeated, or background state in the past:

• Мне нравился этот спектакль. = I liked this play / This play used to appeal to me

So in your sentence, понравился is natural because you are giving your reaction to a specific ending.

Because финал чего? — the ending of what?

Russian uses the genitive case after many nouns when expressing of relationships.

So:

• спектакль = play, performance
• этот спектакль = this play
• этого спектакля = of this play

The phrase means:

• финал этого спектакля = the ending of this play

Both words are in the genitive singular:

• этот → этого
• спектакль → спектакля

Because Russian often expresses relationships like of, ’s, or possession by changing the noun’s case rather than adding a separate word.

So instead of saying:

• the ending of this play

Russian says:

• финал этого спектакля

where спектакля is in the genitive case and already carries the meaning of of the play.

English uses word order and prepositions more; Russian often uses case endings.

The -ся is part of the verb понравиться.

Many Russian verbs include -ся, and its function is not always directly translatable as English self. In this verb, you should learn it as part of the whole word:

• нравиться = to be pleasing, to appeal
• понравиться = to come to please, to be liked

It is best not to break this verb apart too much at first. Just remember that:

• мне нравится... = I like...
• мне понравился... = I liked...

Also note the important contrast:

• Я понравился ей. = She liked me.
• Мне понравился он. = I liked him.

Yes. Russian word order is flexible, though the emphasis changes.

All of these can be natural depending on context:

• Мне понравился финал этого спектакля.
• Финал этого спектакля мне понравился.
• Этого спектакля финал мне понравился. — possible, but more literary or marked

The most neutral version here is probably:

• Мне понравился финал этого спектакля.

Putting финал этого спектакля first can emphasize what you liked.

Usually not in this context.

For reactions to things like films, books, songs, endings, characters, and performances, Russian normally uses нравиться / понравиться, not любить.

• Мне понравился финал этого спектакля. = natural
• Я любил финал этого спектакля. = odd in most situations

Любить means to love or to be fond of, often in a deeper or more habitual sense.

So if you just mean I liked the ending, понравился is the right choice.

You would say:

• Мне не понравился финал этого спектакля.

The structure stays the same:

• мне = to me
• не понравился = did not appeal / I didn’t like
• финал этого спектакля = the ending of this play

If you want a softer or more descriptive past meaning, you might also see:

• Мне не нравился финал этого спектакля.

But for a simple reaction to a specific play or performance, не понравился is usually the best match.

Спектакль usually refers to a stage performance, production, or show, not the written play as a text.

So финал этого спектакля most naturally means:

• the ending of this performance / production

If you wanted to refer more clearly to the written play itself, another word such as пьеса might be used in the right context.

So this sentence most likely sounds like someone watched a performance and is commenting on its ending.

Usually not if you want to say I liked.

• Мне понравился финал этого спектакля. = I liked the ending of this play.

If you remove мне, you get:

• Понравился финал этого спектакля.

That can work only in a context where to whom is already understood, or in very conversational speech where the subject is left implicit. On its own, it sounds incomplete or context-dependent.

So for learners, it is safest to keep мне.

A good rule is:

• with нравиться / понравиться, the person goes in the dative
• the thing liked goes in the nominative

So think:

• Мне понравился фильм.
• Ему понравилась музыка.
• Нам понравилось кафе.

Not:

• Я понравился фильм
• Он понравился музыка

A helpful literal model is:

• The film pleased me
• The music pleased him
• The café pleased us

If you remember that pattern, this sentence becomes much easier to build correctly.