It could just be me, but playing Celeste classic used the d-pad on my switch pro controller, but this one is forcing me to use the analogue stick. It could just be my old school background, but for me that makes the controls very difficult in this one comparitively.
I played this online, but I do have a Switch and I can understand why using the analog stick would make things harder, especially for the first one where you have to do diagonal dashes. Keep in mind this was made in 3 days so they couldn't do that much with it. I'd recommend playing on a keyboard if I were you.