That was my first thought too. Jumping needs to be as near to perfect as you can make it. At the moment it feels like it’s the game’s fault, not mine, if I jump to my death.
Also, I wonder whether the rooms aren’t too big and sparse, given that it’s very easy to die and get sent back to the start. In particular, I didn’t feel like giving the room with the switches a second try after dying near the end. I don’t know what would fix this. Smaller rooms? Save points within a room? Rooms that are more puzzles than platforming? Rooms that are more dense with challenges and danger? Just random thoughts…
Overall it’s good stuff and I hope you keep working on it. If there had been more levels, I would’ve kept playing.
Simon