Each theme for each game requires the FLV of the game. You can get them from Emumovies. My set up has 6 TB HD space so that It can handle all of them. Also Hyperspin is a work in progress, and the themes them selfs are built by people like you and me, that have a desire to contribute. In no way will it come close to being complete, but for the most part its a labor of love.
Regarding playing all of them, its true, I won't, and there are a few I even dislike. But I am a Collector of games. Its nice to know that I have it, if buy chance a friends wants to play it. Some collect coins, that they never cash in, or stamps they never use... Whats the difference?
Also I see it as a way of holding onto our digital past. Retro gaming ***. LOL