Ask HN: What's the most complex application you've built with ChatGPT?

I created a NOLS wilderness first responder custom GPT.

It can give you scenarios of various difficulty and then you need to go through a patient assessment and treatment in the right order.

Can also provide live coaching or give you in field support and direction and help write SOAP reports.

I built this chess game to my satisfaction: https://taonexus.com/chess.html it works on mobile and desktop, supports drag and drop, and the computer plays (badly). All the rules of chess are supported.