I'll probably have a lot more to say about
Blasphemous whenif I actually finish it, but for now... this. So far, the only bit of
Bloodstained crossover content I've found in
Blasphemous is a single room, with the above music playing, in which stands a strange looking door or mirror or whatever it is, which has Miriam's rose symbol on it. I'm not able to interact with it yet. I know Miriam herself is in the game, somewhere, but I have not yet encountered her. I assume that after I meet her, this room will become activated.
(Honestly, it probably would've made more sense to have the
Penitent One as a playable character in
Bloodstained, rather than
Aurora. I mean,
Aurora was cool and all, but still. Or, perhaps, how about both of them? There's no
Blasphemous crossover content in
Bloodstained as of yet, after all.)