Ona ciągle narzeka i marudzi, kiedy mecz kończy się remisem.

No, ona is not strictly necessary here.

Polish verb forms usually tell you who the subject is, so Narzeka i marudzi... already means She complains and grumbles... in context.

Adding ona does one of these things:

• makes the subject explicit,
• adds emphasis,
• helps contrast her with someone else.

So:

• Ona ciągle narzeka i marudzi... = She is always complaining and grumbling...
• Ciągle narzeka i marudzi... = She is always complaining and grumbling.

In everyday Polish, speakers often leave pronouns out unless they want emphasis or clarity.

Ciągle means constantly, continually, or very often always in this kind of sentence.

So Ona ciągle narzeka i marudzi suggests a repeated habit:

• she keeps doing it,
• it happens again and again,
• the speaker may be annoyed by it.

Common near-equivalents:

• ciągle = constantly / all the time
• zawsze = always
• wciąż = still / continually

In this sentence, ciągle fits well because it sounds like ongoing repetitive behavior.

Both are negative-sounding verbs, but they are not exactly the same.

• narzekać = to complain
  This is the more general verb.
• marudzić = to grumble, whine, fuss, moan
  This often sounds more childish, annoying, or petty.

So narzeka i marudzi is a natural pairing meaning something like:

• she complains and grumbles,
• she moans and whines.

Using both together strengthens the idea that she reacts in a very annoying, negative way.

Because the subject is ona = she, and both verbs are in the 3rd person singular present tense.

From the infinitives:

• narzekać → narzeka
• marudzić → marudzi

This is the normal present-tense agreement for she/he/it.

Compare:

• ja narzekam = I complain
• ty narzekasz = you complain
• ona narzeka = she complains

And:

• ja marudzę = I grumble
• ona marudzi = she grumbles

Because Polish, like English, often uses the present tense for habitual actions.

So Ona ciągle narzeka i marudzi does not mean only she is complaining right now. It can also mean:

• this is what she usually does,
• this is her repeated behavior,
• whenever that situation happens, she reacts this way.

The second part also works the same way:

• kiedy mecz kończy się remisem = when a match ends in a draw

This refers to a recurring situation, not necessarily one specific match.

Here kiedy is best understood as when in the sense of whenever.

So the sentence means:

• every time a match ends in a draw, she complains and grumbles.

In habitual statements, Polish often uses kiedy where English might naturally say when or whenever.

Examples:

• Kiedy pada, siedzę w domu. = When/Whenever it rains, I stay home.
• Kiedy mecz kończy się remisem... = When/Whenever the match ends in a draw...

Because kończyć się is the usual way to say to end in the sense that something comes to an end by itself.

• kończyć coś = to finish something
• kończyć się = to end

So:

• Kończę książkę. = I am finishing the book.
• Mecz kończy się remisem. = The match ends in a draw.

The się here is part of the verb phrase and is very important. Without się, the meaning changes.

In this sentence, się is part of the verb kończyć się.

It does not translate neatly word-for-word into English. You should think of kończyć się as a whole expression meaning:

• to end,
• to come to an end.

Many Polish verbs use się in ways that are not truly reflexive in English.

So:

• mecz kończy się remisem = the match ends in a draw

not literally:

• the match finishes itself in a draw

That literal idea is not how this should be understood.

Because after kończyć się in this meaning, Polish commonly uses the instrumental case.

The noun is:

• remis = a draw

In the instrumental singular, it becomes:

• remisem

So:

• Mecz kończy się remisem. = The match ends in a draw.

This is a very common pattern:

• skończyć się sukcesem = to end in success
• skończyć się katastrofą = to end in disaster
• kończyć się porażką = to end in defeat

Because masculine singular nouns often take -em in the instrumental.

Here:

• nominative: remis
• instrumental: remisem

This case is used after certain verbs and expressions, including this one.

A few similar examples:

• problem → problemem
• sukces → sukcesem
• wynik → wynikiem

So remisem is the expected case form after kończy się in this construction.

Because mecz is the subject of kończy się, so it stays in the nominative case.

The structure is:

• mecz = subject
• kończy się = verb
• remisem = complement in the instrumental

So:

• mecz = the match
• kończy się = ends
• remisem = in a draw / as a draw

This is why one noun stays basic and the other changes case.

It can do either, depending on context.

By itself, this sentence most naturally sounds like a general repeated situation:

• whenever a match ends in a draw, she complains.

But if the surrounding conversation is about one particular match, it could also mean:

• when the match ends in a draw, she complains.

Still, because of ciągle and the overall tone, the habitual reading is especially natural here.

The word order is fairly natural, but Polish allows some flexibility.

Neutral version:

• Ona ciągle narzeka i marudzi, kiedy mecz kończy się remisem.

Possible variations:

• Ciągle narzeka i marudzi, kiedy mecz kończy się remisem.
• Kiedy mecz kończy się remisem, ona ciągle narzeka i marudzi.

The meaning stays basically the same, but the focus changes a little:

• putting kiedy... first highlights the situation,
• keeping ona first highlights the person,
• moving ciągle can slightly affect emphasis.

Kończy się is imperfective.
Skończy się is perfective.

In this sentence, the imperfective is natural because the sentence describes a habitual repeated situation:

• when a match ends in a draw,
• whenever that kind of outcome happens.

Compare:

• kiedy mecz kończy się remisem = when a match ends in a draw / whenever it ends in a draw
• kiedy mecz skończy się remisem = when the match ends in a draw / once it ends in a draw

The perfective version sounds more like one specific future event.

That would be too literal and not natural English.

A better translation is:

• She always complains and grumbles when the match ends in a draw.
• She keeps complaining and grumbling whenever the match ends in a draw.

Why not translate literally?

• się is not usually translated as itself
• remisem is better rendered as in a draw
• ciągle often becomes always, constantly, or keeps

So it is better to translate the whole idea naturally, not word by word.