I think right now your background is a bit too high up cause I wanna see the funny mans santa hat and stuff instead of just his legs. You can experiment with this but you can change the height of the background by going to your notepad folder, go to [Events], and change 0,0,"batman jingle bells.jpg",0,0 -> 0,0,"batman jingle bells.jpg",0,XXXX. I would recommend 45 here
Comparing the object count of this map compared to others I don't think there's anything about this map that calls for HP values of the diffs being higher than normal. I'd change Kantan HP9 -> HP8, Futsuu, HP8 -> HP7, Muzukashii HP7 -> HP6. I think top diff is fine, maybe HP5.5 would be better?
Heya!
Looking at various sources on the web, it seems like the title of the song is "Jingle Bells (Batman smells)" with a lowercase 's' for 'smells'. I can't seem to find any other official sources (ex: artist's page).
From Youtube: https://www.youtube.com/watch?v=p8spf6b3k6E