Questions & Answers about Avança dues caselles i després retrocedeix una.
Here it is a command.
In Catalan, the tu imperative often has the same form as the 3rd person singular present. So avança can mean either:
- he/she moves forward in a normal statement, or
- move forward! in an instruction
The context makes it clear that this sentence is giving directions, so it is understood as a command. The same applies to retrocedeix.
A formal vostè command would be different: avanci and retrocedeixi.
Because Catalan often omits subject pronouns when they are not needed.
So instead of saying Tu avança..., Catalan normally just says Avança... The verb form and the context already show that the speaker is talking to you.
In commands, leaving out the subject is especially common. You would only add tu for emphasis, contrast, or irritation.