Responsive Design help

Hi All

I'm really hoping someone may be able to answer some questions I have which are bugging me...

I'm working to create a relatively simple e-learning programme.  It will be mainly a retainer for a number of explainer animations (imported as .mp4s) intermixed with a few fun interactive elements. 

Our user base will mainly be accessing the content on their own personal mobile devises. 

My question is am I best to create my Captivate as a responsive project or not?  Obviously my animated .mp4s will not resize to fit a mobile devise so therefore I will be left with a large empty space on my screen...? 

Also if I do decide to continue using the responsive route when published and viewed on a mobile phone say will the content adapt to both portrait and landscape formats? (when the phone is turned?)

I'm really struggling to find the answers to my questions so any advice / thoughts anyone may have will be extremely helpful.

Many thanks in advance,

Kim