There is still a realistic chance. Interview performance is not graded by counting every visible mistake; interviewers care about the quality of the overall problem-solving process and how you respond when something goes wrong.

One weak interview is not automatically fatal because decisions are usually based on the full set of evidence. The important distinction is between a case that felt uncomfortable and a case that showed repeated failure on core skills.

It is more likely an interviewer-style variation than a separate experienced-hire case format. Real interviews can be much less tidy than prep materials because the interviewer is testing whether you can keep the problem organized even when they do not organize it for you.