@robingranqvist - The issue with that approach is that it does not matter if they watched the video, or are just reading the page. They will be redirected.
@Alessa_Klinger - Youtube does not offer such a feature with the embed. However if you use Vimeo with the player SDK, you can run a script when the video has ended. This requires custom code.
Why not just have a button in the video the user can click on? That you can do in Youtube. See →