Absolutely positioned elements aren't affected by the parents opacity being set to 0. In order to resolve this, set the opacity on the children to "inherit":
.slider-image,
.slider-info {
opacity: inherit;
}
This appears to have resolved the issue for me in IE11.
As was pointed out in the comments above, your document is getting loaded into Quirks mode in some older versions of Internet Explorer. It appears to be the result of the Mark of the Web:
<!-- saved from url=(0014)about:internet -->
This should go below your Doctype, as demonstrated in the linked documentation:
<!DOCTYPE html>
<!-- saved from url=(0014)about:internet -->
<html>