Really cute game, art and sounds are great! I love the mechanic and I feel like it has lots of potential with even more soul types! Maybe even make the way the souls behave necessary from time to time? (like you need to use them to smash through walls). But yeah, really excited for what you do with this!
One thing I will say though is that the spikes and spinning saw blades made me think my character was going to get killed! But in reality, they just do the same speed reduction as all the hazards, right? I would recommend having hazards that look like they will effect the player the way that they actually affect the player (eg. a saw looks like it will hurt/damage/slice the placer, some thick slimy goo on the floor looks like the player would get stuck in it and slow down).
But that's just nit picking, overall nice entry!