Kunludanto metas ludpecojn tiel zorge kiel kontraŭulo.

Kunludanto is a compound word:

• kun- = with, together
• lud- = play
• -ant- = active participant, someone doing the action
• -o = noun ending

So kunludanto literally means a person playing together with someone else. Depending on context, that can mean teammate, fellow player, or co-player.

This kind of word-building is very common in Esperanto.

Because it is:

• plural: -j
• the direct object of metas: -n

Breakdown:

• ludpeco = game piece
• ludpecoj = game pieces
• ludpecojn = game pieces as the direct object

In the sentence, the player is placing the pieces, so ludpecojn is what gets placed.

It is zorge because it modifies the verb metas.

• zorga = careful, as an adjective describing a noun
• zorge = carefully, as an adverb describing an action

Here the sentence is talking about how the player places the pieces, so Esperanto uses the adverb ending -e:

• meti zorge = to place carefully

If it were describing a noun, then -a would be used instead.

Tiel ... kiel ... is a common Esperanto pattern for equality comparison, like as ... as ... in English.

So:

• tiel zorge kiel kontraŭulo = as carefully as an opponent

You can think of it as:

• tiel = that much / so
• kiel = as

This is the normal way to compare equal degree with adverbs or adjectives.

Because kontraŭulo is not the direct object of metas.

The direct object is ludpecojn.
Kontraŭulo is part of the comparison after kiel.

So the structure is basically:

• [Someone] places game pieces as carefully as [an opponent does].

The noun after kiel usually does not take -n unless it has its own grammatical reason to do so.

Esperanto uses la only for definite nouns, roughly like the in English.

There is no word for a/an, so an indefinite noun often appears with no article at all.

That means:

• kunludanto = a co-player / co-player
• kontraŭulo = an opponent / opponent

Whether English uses a, an, or sometimes nothing depends on context, but Esperanto normally just leaves the noun bare unless it is definite.

Metas is the present tense, marked by -as.

So it can mean:

• places
• is placing
• sometimes a general present idea depending on context

Esperanto present tense is often broader than English, so the exact translation depends on the situation.

Not completely. Esperanto word order is fairly flexible, especially because endings show grammatical roles.

This sentence uses a very normal order:

• Kunludanto = subject
• metas = verb
• ludpecojn = object
• tiel zorge kiel kontraŭulo = comparison phrase

You could move some parts for emphasis, but this version is straightforward and natural for learners.

Yes, depending on context, English may translate it either way.

Since there is no la, the most basic reading is an opponent or just opponent. But sometimes English naturally uses the opponent if the situation clearly involves a specific opponent already known from context.

So Esperanto leaves that a bit more open unless definiteness is explicitly marked.

Esperanto strongly prefers building clear compound words.

• lud- = game/play
• peco = piece
• ludpeco = game piece

This is very normal in Esperanto. English often uses separate words where Esperanto uses one compound word. Learning to recognize these compounds is an important skill.