I don't know exactly how flycast works but I've done similar things with other emulators and you take an action in the game (take damage, type something), then

I don't know exactly how flycast works but I've done similar things with other emulators and you take an action in the game (take damage, type something), then search memory for that value. In this case the ascii code for the letter typed. Keep doing this until you've narrowed down a single block of memory that holds everything you've done