A 1cc of Toho Feveron on the hardest settings, at least according to the developer.
If you want to see what the other stages are like, check this video out: • Touhou: Suimu Souran-k...
Hard mode is something that can be enabled through a text file, all it does is add Ketsui-esque revenge bullets to all enemies, this significantly makes stage portions harder.
There are 2 scoring systems in the game, it's set to Original in the text file by default. I played on Standard mode, this makes it so enemies drop score items instead of doing the whole "shoot unfocus when there are a lot of bullets near the enemy to build up a points counter" thing... yeah, Original is kinda weird. Standard apparently gives you more score, but at the cost of not being able to cancel bullets around defeated enemies using your focus shot, this makes survival more challenging... I guess?
I went with route A'CFJNT because I believe this is one of the safest routes for a clear, but only because I have to fight Yuyuko as my final boss who is pretty chill (the Zone T stage is absolute hell on hard mode though, thanks to the dumb revenge bullets). I can imagine route A'CFJOP would be the hardest thanks to the silly stage portion in Zone O and literally everything in Zone P.
Download (no BGM included, requires Danmakufu 0.12m): mega.nz/file/NU4xFLxS#CAgRdHg...