The landing page took quite some time to load for me and I was wondering why it loads so much JavaScript. I think Angular is only needed for the actual application, not the static content pages, isn't it? Would load faster that way.
Btw: Your German translation is so bad, I would rather keep it English. "Premium" is translated as the German word for "bonus" or "bounty", while "Premium" itself is a perfectly fine German word. This probably hurts the conversion rate more than it helps.
Maybe use a looped embedded video instead of GIF? You can get much higher quality with a smaller file size. If you have a lot of users on IE8, you could fallback to GIF.
Mind explaining what you mean why this should be a client side app?