Very interesting concept! I find this game quite difficult but it was fun positioning all the platforms just right to cover as much ground as possible.
To make this game even better, I would suggest more visual cues to separate different platforms. For example, the souls will stick to the shorter platform when moved, but visually the shorter platforms are the same as the larger ones. Another suggestion is to let the souls drop down infinitely. Having to reload because of 1 mistake can be quite frustrating. You can introduce a fail count if you want to reflect players' mistakes.
Overall a very good game with a simple but fun design. Nice attempt!