It could mean the end of a time period for watching something. For example, if there is a limited time to watch a show or an event, 'watch period end of story' might imply that the time to watch has come to an end and that's all there is to it.
Sure. Let's say there is a free trial for a streaming service that lasts for a week. That week is the watch period. When the week is over and you can no longer access the content for free, it's the 'watch period end of story'.
In some contexts, 'period end of story' is used to emphasize the end of a sequence or an event. Let's say a semester in school has ended. You could say 'period end of story' to sum up that that particular period of study has concluded and there's nothing more to add regarding that specific semester.
It could be the best ever period because of a culmination of amazing experiences. Maybe it was a time of great personal growth, achieving long - sought - after goals, or having a series of really positive and fulfilling events. For example, if someone had been working hard on a project for years and finally completed it successfully during that period, it would be a strong candidate for being the best ever.
I'm not entirely sure what 'imdb period end of story' specifically means. 'IMDb' is the Internet Movie Database, but the 'period end of story' part is rather unclear. It could potentially be some sort of statement about a particular period related to a movie or TV show on IMDb, like the end of a specific era or time frame for a certain production, but without more context, it's hard to say for sure.
I don't know who did the translation. Usually, a good translation should convey the meaning precisely while maintaining the style and tone of the original. But it's hard to say for sure without looking at this specific one.
It could mean the best time ever and that's the final conclusion. For example, if someone says about a vacation 'It was the best ever period end of story', they're saying it was an extremely great vacation and there's no more to add or discuss about how good it was.