Thank you so much for your warm encouragement and great suggestion!
ヽ( ´ ∇ ｀ )ノ
Actually the layout of the upstairs is one of the key points of this game. I was thinking about this point a lot. Can't say that the current implementation is the best, but I'm feeling kind of OK with that so far. Yeah, you can't see enemies behind the wall, but I see it's a kind of interesting challenge. Not too bad for me.. (´・ω・｀)
With that said, if more people will complain about this problem, I will think of revising the current implementation.
"Outlining enemies behind the wall" is a simple solution. Maybe we don't need to show the outlines all the time. Occasional flickering could serve the purpose..
Anyway, I really appreciate your feedback. Thanks! (´▽｀)