When would you even use this? I can only imagine someone saying, "Day 3: Our subject has yet to speak. However, it is playing."
German doesn't have the distinction between the English tenses "it plays" and "it is playing" -- the sentence can be translated either way, with no helper verb in the German.
the first and logical step is naturally to think of the pronoun for neuters. But this would not explain the idiomatic usages:
es ist 10 Uhr
es spielt keine Rolle was Du willst
Es klappert die Mühle (Kinderlied).
es scheint die Sonne.
In most cases, where Es is the Subject and the verb follows directly, it must not agree with the gender of the virtual subject. But I think you have the same idea in English. Who is at the door? It is my sister.
'Spielt' is in English 'plays'. 'It is plays' is not correct either in English. The present progressive form 'is playing' doesn't exist in German. 'He is playing football' is in German: Er spielt (gerade) Fußball. Das Radio (es) spielt wieder (is playing again). But also 'das Kind' (the child) and 'das Mädchen' can be 'es' because the article is 'das'. For 'das Mädchen' I can also use the pronoun 'sie': sie spielt gerade.