Keglefaldet er højt efter striken.

Because Danish normally writes compound nouns as a single word.

Here, keglefaldet is built from:

• kegle = pin
• fald = fall / drop
• -et = the definite ending

So Danish treats it as one compound noun, not as separate words. This is very common in Danish, even where English might prefer two words.

That is because Danish has two grammatical genders:

• common gender nouns usually take -en in the definite singular
• neuter nouns usually take -et in the definite singular

So:

• et keglefald → keglefaldet
• en strike → striken

The last part of a compound usually decides the gender, so keglefald takes its gender from fald, which is neuter.

In Danish, the is often added to the end of the noun instead of appearing as a separate word in front.

So:

• keglefaldet = the pinfall
• striken = the strike

A separate word such as den or det is usually used when there is an adjective before the noun:

• det høje keglefald = the high pinfall

But when the noun stands alone, Danish usually prefers the ending on the noun itself.

Because keglefald is a neuter singular noun, and the adjective must agree with it.

The adjective høj becomes:

• høj with common gender singular
• højt with neuter singular
• høje with plural or definite attributive use

So:

• en bygning er høj
• et tal er højt
• keglefaldet er højt

Even though the adjective comes after er, it still agrees with the noun.

It is an adjective, not an adverb.

It describes the subject keglefaldet, so it is a predicative adjective after er.

That matters because English speakers often see the -t ending and think adverb, but here the -t is showing neuter agreement, not adverb formation.

Because Danish often borrows English words and then uses normal Danish grammar with them.

So strike can behave like an ordinary Danish noun:

• en strike
• striken

That is very common with sports and technical vocabulary. Even if the word originally comes from English, Danish still adds Danish endings to it.

Yes.

• efter en strike = after a strike
• efter striken = after the strike

So the version in your sentence is definite: it refers to a specific strike that is already known from the context.

Yes, it can.

You can say:

Efter striken er keglefaldet højt.

That is still correct Danish. But if you move that phrase to the front, the verb er must still stay in second position. That is a normal Danish word-order rule.

So:

• Keglefaldet er højt efter striken.
• Efter striken er keglefaldet højt.

Both are possible, just with a different emphasis.