Meðmælin og gagnrýnin komu eftir frumsýninguna.

In Icelandic, the is often attached to the end of the noun instead of appearing as a separate word.

In this sentence:

• meðmælin = the recommendations / praise
• gagnrýnin = the criticism
• frumsýninguna = the premiere

So the definiteness is built into the noun itself.

Because the subject is made of two things joined by og (and):

• Meðmælin
• gagnrýnin

Even though gagnrýnin is singular by itself, the whole subject is compound, so Icelandic uses a plural verb.

That is why you get:

• komu = came / arrived (plural past)

If there were only one subject, you would expect a singular form instead.

They are in the nominative case, because they are the subject of the sentence.

They are the things that came:

• Meðmælin og gagnrýnin komu ...
• The praise/recommendations and the criticism came ...

So they appear in nominative forms.

Because after the preposition eftir in the sense of after (in time), Icelandic uses the accusative.

So:

• frumsýning = premiere (dictionary form)
• frumsýninguna = the premiere (accusative singular definite)

That ending shows both:

• definite meaning (the)
• accusative case

Yes. Komu is the past plural of koma, which literally means come.

But in Icelandic, just like in English sometimes, come can be used a bit more broadly. Here it means that the reactions appeared or followed after the premiere.

So depending on context, a natural English rendering might be:

• came after
• followed
• appeared after

In this kind of meaning, meðmæli is very often used as a plural noun.

So meðmælin here is a plural definite form, meaning something like:

• the recommendations
• the praise
• the positive reviews

A learner may expect a singular form, but this word is commonly used in the plural for this kind of idea.

Because Icelandic noun endings change depending on gender, number, case, and definiteness.

Here:

• gagnrýnin is feminine singular nominative definite
• frumsýninguna is feminine singular accusative definite

So even though both nouns are feminine singular and definite, they are in different cases, and that changes the ending.

This is very normal in Icelandic: the definite article changes shape depending on the grammar of the noun.

They are close to opposite kinds of reactions.

• meðmæli usually suggests approval, endorsement, praise, or positive recommendation
• gagnrýni means criticism, but it can also mean critique or even review, depending on context

So together they suggest that both positive and negative reactions came after the premiere.

Yes. Icelandic word order is fairly flexible.

For example, you could also say:

• Eftir frumsýninguna komu meðmælin og gagnrýnin.

That puts more emphasis on when it happened: after the premiere.

Both versions are grammatical, but the emphasis shifts slightly depending on what comes first.

Correct: common nouns are not capitalized in Icelandic just because they are nouns.

So:

• meðmæli
• gagnrýni
• frumsýning

are normally written with lowercase letters.

Meðmælin is capitalized here only because it is the first word of the sentence.