The polite lie of the portfolio site
The work you can show is almost never the work that mattered. The NDA shelf is always the better portfolio.
The shiny stuff shows
Your portfolio is selection-biased toward work that was visual, shippable, and non-confidential. That's a small slice of the actual job, and not usually the most valuable slice.
What to say instead
Talk about the decision, not the deliverable. 'Here's what we almost shipped, and why we didn't' is a better signal than a screen. Nobody asks about the screens once you've said something interesting about the decision.