I beat the first level, but was not able to get through the second. The jerky movement just didn't work for me. It took me a bit to realize the platformer part relied on tapping the buttons and did not allow holding to move. I'd say part of that was there being such short sections and immediate jumping that I was naturally doing a lot of tapping to start, until I got to a bit where I just wanted to keep moving and stopped. It would be nice if you added the list of controls and a bit of instructions to the web page or in game.
It was also odd going from the slow and smooth top down, hold a button to continue moving, of the opening area, to the jerky press a button to move quickly a short distance and stop, of the side scrolling levels. Resetting back to the left side of the initial area and having to slowly walk across it to the door, to then go back to the jerky movement likely made it feel worse. The long walk certainly was annoying to have to do each time you restarted. It would be nice to be able to restart on the level you were on, but even if you make the player restart at the beginning, let people quickly get back into playing. I didn't notice anything in the opening area, other than the door, so that long slow walk might be OK for the start, but doesn't feel like it serves a purpose for the retries. With the very different controls, I'd personally drop the movement on the opening area, or change it to be like the platforming sections.
The level design seemed decent on the 2 I saw. I wasn't good enough with the controls, but could see the path to beat the second one. The danger spots were clear. The collision detection felt decent. This feels like a good start.