The video is a background video which cannot play on mobile since mobile OSes disallow automatic video playback to help conserve limited resources like battery on mobile. If you need a video to play on mobile, you will need to use the video embed provided by YouTube/Vimeo and play the same not as a foreground video.
You can make the image clickable pointing to the portfolio page by having this custom CSS –
.type-portfolio .image-info {
display: none;
}
.type-portfolio .image-overlay {
display: none;
}
It will disable the text on image and instead make the image clickable.