Baraja, reparte y retrocede dos casillas.

It is a sequence of commands or instructions.

In English, this would be the kind of language you see on a game card, in rules, or in step-by-step directions. Spanish does the same thing here: it gives direct instructions to one person, with the subject left unstated.

The implied subject is tú:

(Tú) baraja, reparte y retrocede dos casillas.

Spanish often leaves the subject out when it is obvious from the verb form.

They are affirmative tú commands.

For many regular verbs, the affirmative tú command looks the same as the él/ella/usted form of the present tense:

• barajar → baraja
• repartir → reparte
• retroceder → retrocede

So this sentence is telling one person to do three things:

• baraja = shuffle
• reparte = deal / distribute
• retrocede = move back / go back

A useful comparison:

• Present statement: Él baraja. = He shuffles.
• Command: Baraja. = Shuffle.

They look the same, but the meaning comes from context.

It is informal singular, meaning it is directed to tú.

If it were a formal usted command, it would be:

Baraje, reparta y retroceda dos casillas.

If it were aimed at several people in most of Latin America, it would usually be:

Barajen, repartan y retrocedan dos casillas.

Because you mentioned Latin America, it is also worth knowing that in voseo regions, many speakers would use forms like:

Barajá, repartí y retrocedé dos casillas.

So the sentence you were given is standard tú Spanish, which is widely understood across Latin America, even though some countries commonly prefer vos in everyday speech.

Because Spanish normally omits subject pronouns when the verb already makes the subject clear.

In English, you usually need you for commands only if you want emphasis. In Spanish, the command form itself already tells you that someone is being addressed directly.

So:

• Baraja, reparte y retrocede dos casillas
  is completely natural.

Adding tú would sound more emphatic:

• Tú baraja, reparte y retrocede dos casillas.

That is possible, but usually unnecessary.

Not in this sentence.

Baraja can indeed be a noun meaning deck of cards, but here it is clearly a verb because of the structure:

• Baraja, reparte y retrocede...

That pattern is a list of commands, so baraja is understood as shuffle.

If it were the noun, you would normally expect an article or another determiner, such as:

• la baraja = the deck
• una baraja = a deck

So in this sentence, baraja is from the verb barajar.

Here, reparte means deal if the context is a card game.

The base verb repartir has a broader meaning: to distribute, to hand out, to give out. But in game contexts, especially with cards, it often translates naturally as deal.

So depending on context:

• repartir cartas = to deal cards
• repartir comida = to hand out food
• repartir folletos = to distribute flyers

In your sentence, deal is the most natural game-related meaning.

In this context, casillas means spaces or squares on a board game.

So:

• retrocede dos casillas = go back two spaces

The singular casilla can mean different things depending on context, such as:

• a little box
• a square
• a cell
• a slot
• a space on a board

In board games, casilla is a very common word for one marked position on the board.

Because casilla is a standard Spanish word for a marked square or space in games, forms, grids, and similar layouts.

A native English speaker may expect something closer to espacios, but in board-game language casillas is often the more idiomatic choice.

So:

• avanza tres casillas = move forward three spaces
• retrocede dos casillas = move back two spaces

You may also hear other words in some contexts, but casillas is very normal here.

The commas separate the first items in a series of commands, and y joins the last one.

This works much like English:

• Baraja, reparte y retrocede dos casillas.

Spanish normally does not use a comma before the final y in a simple list, unless there is some special reason for clarity or style.

So this punctuation is standard.

Because Spanish often leaves out information that is already obvious from the context.

In a game, the listener probably already knows what is being shuffled and dealt, most likely the cards. So Spanish can simply say:

Baraja, reparte y retrocede dos casillas.

A fuller version could be:

Baraja las cartas, reparte las cartas y retrocede dos casillas.

But that sounds more repetitive if the context already makes it clear.

Yes.

The verb retroceder means to go back, to move back, or to retreat, depending on context. In a board game, it means to move your piece backward on the board.

So:

• retrocede dos casillas = move back two spaces

It can also be used outside games:

• El ejército retrocede. = The army retreats.
• El coche retrocedió. = The car backed up.

In your sentence, the board-game meaning is the natural one.