Right now, the Spanish word in the phrase for "autoplay" is a combination of "automatic" and "play", but it's not a recognized word. Also, it sounds unnatural to Spanish speakers. "Reproducir" is a common verb when it comes to multimedia, and with the addition of "automáticamente", the phrase is totally covered in Spanish.

I decided to use this new translation to make it as short (while still self-explanatory) as possible.

This new translation is even shorter than the one above (while still self-explanatory).

The right translation for Autoplay would essentially be Autorreproducir, so there was no need to modify the translation with neologisms of any sort.