Μετά το ημίχρονο το σκορ αλλάζει και γίνεται δύο δύο.

Because μετά meaning after is followed by the accusative in Modern Greek.

• μετά το ημίχρονο = after halftime
• το ημίχρονο is the accusative form, and for this noun it looks the same as the nominative.

So this is a very common pattern:

• μετά το μάθημα = after the lesson
• μετά το παιχνίδι = after the game

Because ημίχρονο is a neuter singular noun, so it takes the neuter singular article το.

• το ημίχρονο = the halftime

The same is true for το σκορ later in the sentence: σκορ is also treated as a neuter singular noun.

Ημίχρονο means halftime or half-time in a match.

It is built from:

• ημί- = half
• χρόνος = time

So literally it has the idea of half-time.

Greek usually uses the definite article much more regularly than English.

So even if English might say simply after halftime, the score changes, Greek naturally says:

• Μετά το ημίχρονο το σκορ αλλάζει...

Here:

• το σκορ = the score

Also, σκορ is a loanword, but in Greek it is commonly treated as a neuter noun, so το is the normal article.

Αλλάζει is the 3rd person singular present tense of αλλάζω = to change.

So:

• αλλάζω = I change
• αλλάζεις = you change
• αλλάζει = it changes / he changes / she changes

In this sentence, the subject is το σκορ, so:

• το σκορ αλλάζει = the score changes

This is very common in Greek, especially in narration and sports language. Greek often uses the present tense to make an event feel vivid or immediate.

So:

• το σκορ αλλάζει literally = the score changes
• but in context it may correspond to English the score changes, the score changed, or the score becomes, depending on the style of translation.

This is similar to the historic present in English, especially in commentary:

• He passes, he shoots, he scores!

Γίνεται is the 3rd person singular of γίνομαι, which means to become, to happen, or to be made, depending on context.

Here it means:

• γίνεται δύο δύο = it becomes two-two

So the sentence has a natural sports-commentary structure:

• the score changes and becomes 2–2

Greek often likes this kind of double expression because it sounds natural and clear.

• το σκορ αλλάζει = the score changes
• και γίνεται δύο δύο = and becomes two-two

The first verb gives the general action: it changes.
The second gives the result: it becomes 2–2.

In English we might sometimes just say:

• After halftime, the score changes to 2–2.

But Greek often expresses both steps.

In spoken Greek, scores are very often said by simply repeating the numbers:

• ένα μηδέν = 1–0
• δύο ένα = 2–1
• δύο δύο = 2–2

So δύο δύο is the natural spoken form of 2–2.

You may also hear:

• δύο προς δύο

But simple repetition is extremely common in everyday speech and sports commentary.

Because in Greek, when reading out a score, the two numbers are often just placed one after the other.

So:

• δύο δύο literally = two two
• functionally = two-two / 2–2

This is just the normal way of expressing a score orally.

Yes. The subject of both verbs is το σκορ.

So the structure is:

• Μετά το ημίχρονο = after halftime
• το σκορ = the score
• αλλάζει = changes
• και γίνεται δύο δύο = and becomes two-two

Greek does not need to repeat the subject a second time, because it is already understood.

No, Greek word order is fairly flexible, although this version is very natural.

• Μετά το ημίχρονο το σκορ αλλάζει και γίνεται δύο δύο.

This order puts the time phrase first:

• After halftime...

That is a very normal choice because it sets the scene before telling us what happens.

Other orders are possible for emphasis, but this one is straightforward and idiomatic.

A fairly literal version would be:

• After halftime, the score changes and becomes two-two.

That is not the most natural final English phrasing, but it helps show how the Greek sentence is built.

A more natural English version would usually be something like:

• After halftime, the score changes to 2–2.
• After halftime, it becomes 2–2.