Something I thought've that may be a cool item once everything else is out of the way or when the city is accessible is pump shoes, Shoes that have the air pumps on the bottom of them so every step you take pumps air, could also be useful if there was a running system to be included with said shoes.
Otherwise, I haven't noticed any real bugs in the windows version save for the fact that Ayume will sleep sideways on the bed within the blue room on the second floor, other than that its pretty good so far.