yeah, that trapdoor reopening after using the keys wasn't intentional. Thanks for sticking with it until the end.
I have a new build ready to go with the relevant bugs fixed and a lot of polish of existing mechanics (lighting is dramatically better, you can look up/down through holes to other floors, keyhole is more than just a sticker on the wall) but no significant changes to content. (you might notice a few minor differences in the test room if you return there)
I have a lot of dungeon components to add and to finish combat, and to include audio before I return to dungeon layout, but I do intend to stick with it until I have a finished game that will take more than a minute to run through :)