For me, it wasn't just the date by itself. I think the general premise (beginning and middle being like Hostel) sounds arbitrarily specific, and such levels might get kinda repetitive if this is actually a thing. Hostel seemed to be like a running gag of sorts for some reason. If it wasn't for that, and it was just about making any kind of post-game looking level, I might have taken it a bit more seriously, even if it was on April 1st.
--------------------Legacy custom music
How am I so creative? I think taking walks might have something to do with it.
Every single level of every single ROM hack I've ever made is easier than Ultra Necrozma.