On Megalovania difficulty I felt like some specific sliders should be a bit slower 20:09:315 (1) -, 20:21:315 (1) -, 20:25:315 (1) - and 20:37:315 (1) -, to represent the extended sound. I also felt like the inherited point on 21:55:315 - should be a bit slower than 0.75x, maybe 0,7x or 0,65x, because the sv goes up suddenly, it made me think it would be 1,0x+ again.
I dont think reducing the SV for the first set of sliders you said makes sense to me, but the second point sounds nice so I'll lower the end a bit
I also went ahead and did some other things! Fixed the breaks, minor tweakies, and increased the HP of the /main marathon/ The other difficulties can be like training or some sort, but if you wanna pass the BIG marathon, you'll need to put the training to the test