I should also consider mobile app development if the target audience is mobile users. Developing a dedicated app for downloading the show could offer a better user experience compared to a web-based one.

Notifications and Feedback: Informing users when the download is ready or if there's an error. Maybe sending a download link to their email after a successful purchase.

Now, putting this into a feature specification. The user might need a step-by-step plan for developing the feature. Starting with defining user stories, then moving through design, development, testing, and deployment phases.