hey, thanks for playing my game and for your feedback!
the navigation definitely could have been better! i didn't really get time to playtest it all that much. also, not much of a spoiler, but for the checklist items, they don't always generate in the same rooms, and the location of the last three depend on which floor you visit after the ground floor, but there are always two items to interact with on the ground floor, one in the basement, and two in the attic.
in your case, it is however not impossible that there was a glitch in the map creation process that a room could've been inaccessible. sorry about that!