Video files aren't supported yet, although it's on my "to do" list for a future version - possibly the next version.
You can play animated GIFs though, and they can play at the same time as sound files - just put them in the same script. There is a "Show an animated GIF" command in the "Pictures & Sounds" category.
There's no way of integrating a game into a website yet, but you can link to the "Play online" feature when you upload a game to
www.textadventures.co.uk. I'll be adding a way of embedding games in other websites at some point, but in the meantime you could probably do it via an <IFRAME> tag.