Min syster skrev en kort recension där hon sa att huvudpersonen kändes som en riktig person.

In Swedish, you normally do not use an article before a noun when it already has a possessive like min, din, hans, hennes, vår, and so on.

So:

• min syster = my sister
• not en min syster
• not den min syster

This is different from English only in form, not meaning. The possessive already makes the noun definite enough.

Skrev is the past tense of skriva = to write.

So:

• skriva = to write
• skriver = writes / is writing
• skrev = wrote
• skrivit = written

In this sentence, Min syster skrev... means My sister wrote...

Recension is a common-gender noun in Swedish, so it takes en in the indefinite singular.

• en recension = a review

The adjective kort must agree with the noun phrase. Since recension is an en-word, the adjective in the indefinite singular common-gender form is kort.

So:

• en kort recension = a short review

Compare:

• en kort bok would be wrong, because bok is not neuter; actually it would still be en kort bok because kort is one of those adjectives whose common-gender and neuter indefinite forms can look the same in some contexts? Better comparison:
• ett kort brev = a short letter

Here kort already has the form used in the indefinite singular.

Yes, där literally means where, but in this sentence it works more like in which or where referring back to recension.

So:

• en kort recension där hon sa... = a short review where/in which she said...

This is natural Swedish, even though English often prefers in which or just where less often with things like review.

Swedish uses där quite freely to connect to a place, situation, text, or context.

Yes, i vilken is possible, but it sounds more formal and more written.

• en recension där hon sa... = normal, natural
• en recension i vilken hon sa... = more formal, more stiff

In everyday Swedish, där is much more common here.

Att here is the conjunction that.

So:

• hon sa att... = she said that...

It introduces a subordinate clause.

Swedish often uses att in the same way English uses that, although in both languages it can sometimes be omitted in more casual speech. In careful written Swedish, keeping att is very normal.

Both sa and sade are past-tense forms of säga = to say.

• sa = shorter, very common
• sade = also correct, slightly more formal or traditional in tone

So both of these are correct:

• hon sa att...
• hon sade att...

In modern everyday Swedish, sa is extremely common.

Huvudpersonen means the main character.

The base word is:

• huvudperson = main character / principal person

The ending -en makes it definite:

• huvudpersonen = the main character

This is very typical Swedish. Instead of putting a separate word like the before the noun, Swedish often adds definiteness to the end of the noun.

This is a very important difference.

• kände is the past tense of känna = to feel, to know, to be acquainted with
• kändes is the past tense of kännas = to feel, to seem

In this sentence, the meaning is seemed/felt like, so Swedish uses kännas:

• huvudpersonen kändes som en riktig person = the main character felt/seemed like a real person

If you said kände, it would suggest that someone felt something directly or knew someone, which is not the meaning here.

Yes. Kändes som is a very common Swedish structure.

Examples:

• Det kändes bra. = It felt good.
• Det kändes som en dröm. = It felt like a dream.
• Han kändes ärlig. = He seemed honest.
• Huvudpersonen kändes som en riktig person. = The main character felt/seemed like a real person.

So in this sentence, kändes som is completely natural.

Here som means like.

So:

• kändes som en riktig person = felt/seemed like a real person

This is a standard structure:

• kännas som + noun phrase

Examples:

• Det känns som sommar. = It feels like summer.
• Hon kändes som en vän. = She felt like a friend.

Riktig often means real, genuine, or proper, depending on context.

Here, en riktig person means something like:

• a real person
• a genuine person
• an actual person

In this sentence, it suggests the main character felt believable and lifelike, not artificial or flat.

Swedish also has verklig, which can also mean real, but riktig person is very natural here.

This is because Swedish keeps normal main-clause word order in the relative clause after där until you reach the subordinate clause introduced by att.

Break it down:

• där hon sa...
  This part behaves like a clause with normal subject-verb order: hon sa

Then inside it:

• att huvudpersonen kändes som en riktig person
  This is a subordinate clause introduced by att

Inside that clause, the subject comes before the verb:

• huvudpersonen kändes...

So the structure is:

• main clause: Min syster skrev en kort recension
• relative clause: där hon sa
• subordinate clause: att huvudpersonen kändes som en riktig person

Not naturally in this sentence.

• där hon sa... refers to the review as the place/context in which something was said
• som sa... would mean that/which said..., making the review itself the subject of said, which sounds odd

So:

• en recension där hon sa... = a review where/in which she said...
• en recension som sa... = a review that said...

The second one is grammatically possible in some contexts, but it sounds less natural here because a person says something in the review.

Usually recension means a review of a book, film, play, album, and similar cultural works. It often sounds a bit more like a published or formal review.

For other kinds of reviews, Swedish may use other words depending on context, but recension is exactly right for something like a written critique of a story or book.

A fairly literal breakdown would be:

• Min syster = my sister
• skrev = wrote
• en kort recension = a short review
• där = where / in which
• hon sa = she said
• att = that
• huvudpersonen = the main character
• kändes som = felt like / seemed like
• en riktig person = a real person

So the whole structure is very close to:

My sister wrote a short review where she said that the main character seemed like a real person.

Yes, it is natural and idiomatic Swedish.

A native speaker would understand it immediately, and nothing about it sounds unnatural. In particular:

• skrev en kort recension is normal
• där hon sa att... is natural
• huvudpersonen kändes som en riktig person is very natural for describing believable fiction

So this is a good example of standard written Swedish.