I like the artwork of the main character, and the early to middle part of the run felt reasonable.  The distribution of the generation of the platforms, hearts and bad souls felt fair. The location if where items drop could be refined further, as occasionally a bad soul or a heart can drop directly onto the player.

The jump control was very responsive at the start of jumps. However, it always jumps to a specific height. This makes it difficult towards the end, as the player character was too far to the right-hand side to reasonably react to gaps. This made it a gamble between jumping early in case the next platform is very short or jumping later in case the platform is very high.

Having a a variable jump height (short button press for short hop, long button press for larger leaps) and a method of slowing down would help mitigate this. 

For slowing down, I initially thought that the bad souls could subtract points and slow down the player. However, this may defeat the purpose of your story element of avoiding bad souls, so perhaps a different item drop may be needed or have the player position fixed whilst speeding up the rate that the platforms pass the player.

It will be interesting to see how this game develops and what you decide to do with it.