The game takes a bit to find it's footing, but once it does it's pretty fun! I think it really clicked for me during the maze part. This is when I got from "It has some potential" to "I'm having fun!". Now- I'll be serious here. I didn't really notice how the stats affected the gameplay. I upgraded the strength, or agility, but my guy seemed to move the same. I didn't mind- the game was more about moving boulders onto buttons :)
The sound was ok. I liked how the "soul pickup" sound had slight variations! The graphics could use some work though. I mean- the guy looked ok, and the characters in the cutscenes were charming, but some more visually appealing floor tiles would be nice. Also- it took me a minute to tell, that the darker wall was climbable. A ladder tile would work better :)
As for the use of the theme... I got it in the end, but for the most of the game I thought "but I AM saving them all". Whet I'm saying is that you could have used the theme in a more visible way.
Over all- the game needs polish, but has potential! Keep it up!