Well, while I thought it was quite difficult finding the 6, I have to say that all around this is a great game! The platforming is pretty good, it adheres to the theme really well, and the puzzles were good, both in and out of the platforming sections!
A couple of things I noticed, these aren't major complaints just little things :)
Firstly, the reading of the dialogue was a bit annoying when it was overlaid over other things. I'd say either give it an opaque black/grey background, or move it somewhere where there is less going on (the menu button kept coming up behind dialogue choices)
The platforming was all around pretty good, but there were a couple of tight jumps that felt quite difficult to do, mostly because if you did a run up it was quite hard to judge when was the correct time to jump, because if you timed it too late you'd just fall but the energy would still be used. I think this is probably a simple thing to fix though!
This isn't your fault, because you did make it really clear (but when the game is lying to you...) I pressed the reset save button, and ended up having to replay the first 6 levels. You did put the warning there, but I think it would be better to not show the button until the final credits screen, just to make sure nobody accidentally presses it!
Other than these things though, I think it is a solid game and does well both at adhering to the theme and in having good platform puzzle elements. Only other thing is to suggest some audio ;)