I'm a big fan of games with deliberate/limiting movement & combat mechanics, like NES Castlevania & La-Mulana; so I was very happy to see that kind of thing here & I respect your choice in doing it.
I played on v1.1 & didn't have any issues on my PC, although I did spot a bug where getting killed mid-whip (I think?) would allow me to stay alive on 0 hearts.
I think the layout & checkpoint placement was great & I never got frustrated or confused about where to go or what to do; whipping enemies off the screen was very satisfying too.
As it stands, the whip's attack frame does feel like it lasts just a little too long, although it feels fine when in the air - I think this might be due to the fact that you retain some ability to move left & right when whipping in the air; maybe it'd help if you had similar very-slow movement control when whipping on the ground.
The difficulty/level design was pretty good, although I think a couple of the platforming challenges were a little tight / felt like they were designed for a game with more fluid movement. The wall-jump section with the two arrow shooters either side was kinda tight, although I really liked the room itself & the way you could get to different areas from it.
I also thought the arrow shooter at the bottom of the moving platform section just served to bother you while you waited for your chance to grab the moving block.
Despite these little nitpicks, I had a good time playing this & got my 50 coins.