Most question banks are paywalled, so I built a free one: Critical, 299 branching clinical cases for USMLE Step 2 CK.
How it works. You get a patient presentation and choose your next move: order a test, make a diagnosis, start a treatment. Each choice leads somewhere different, and every path ends with a debrief that explains why it was right or wrong and cites the guideline or trial behind it.
How it's built. It's written in Twine with the Harlowe story format and exported as one static HTML file. It's hosted on GitHub Pages, so there's no backend, no login and no data collected beyond anonymous page-visit counts.
Limits. It's a practice tool, not medical advice, and no physician has formally reviewed the full bank yet. If you find an error, open an issue on GitHub.
Try it: https://xairu23.github.io/Critical/
Source: https://github.com/xairu23/Critical
I'd like to hear what would make it more useful to people studying for Step 2.