Learn Hardcore Dutch: Ons gesprek eindigt halverwege de maaltijd, omdat de camera uitvalt. - Our conversation ends halfway through the meal because the camera fails.

In Dutch the possessive ons is used before a het-word (a neuter noun) and onze before a de-word (a common gender noun). Since het gesprek is neuter, you use ons gesprek.

Why is the verb eindigt in the singular form, even though we’re talking about “our conversation”?

The subject of the verb is gesprek, which is a singular noun (one conversation). So you conjugate eindigen in the third person singular: eindigt.

What does halverwege mean and how do you use it?

Halverwege means “halfway through” or “in the middle of.”

It can function like a preposition or adverb.
You follow it directly with the noun phrase, without adding van.
Example: halverwege de maaltijd = halfway through the meal.
You can also use it alone: Halverwege viel het licht uit. (“Halfway through, the power went out.”)

Why is uitvalt placed at the end of the clause introduced by omdat?

Omdat is a subordinating conjunction (a subordinator). In Dutch subordinate clauses, the finite verb moves to the very end. Also, uitvallen is a separable verb, so uit + valt combine as uitvalt and sit together at the end of the clause.

What’s the difference between omdat and want when you want to say “because”?

omdat introduces a subordinate clause and pushes the verb to the end.
want is a coordinating conjunction and keeps the normal main-clause word order.
Example with omdat:
Ons gesprek eindigt halverwege de maaltijd, omdat de camera uitvalt.
Example with want:
Ons gesprek eindigt halverwege de maaltijd want de camera valt uit.

Is the comma before omdat mandatory?

In Dutch it’s common to separate a main clause and a subordinate clause with a comma, so you’ll often see:
…eindigt halverwege de maaltijd, omdat…
Strictly speaking the comma is not 100% mandatory, but it clarifies the sentence structure and is recommended.

Could you start with the omdat-clause? How would the word order change?

Yes, you can place the subordinate clause first. You keep the verb at the end of that clause, then follow with the main clause in normal word order:
Omdat de camera uitvalt, eindigt ons gesprek halverwege de maaltijd.
Notice:

Subordinate clause with verb at the very end.
Main clause starts with its verb in second position: eindigt ons gesprek…

Why is it de maaltijd and not het maaltijd?

Some Dutch nouns use de, others use het. Maaltijd is a de-word (common gender), so it takes de. There isn’t always a rule—you often have to learn which noun uses which article.