This is an excellent game concept and all the ideas in it have been implemented really really well. It took me a while but I managed to complete the game. It felt like the levels started out hard and then got a bit easier(not a whole lot easier, though). One issue I had is that I didn't feel like the game was rewarding me for figuring out the puzzles. Each level's text in general is very negative and disheartening. Even when you reach the end... it isn't much of a reward... maybe some sort of cutscene or something where the hands find some large golden Aorta would have been better, I don't know.
I can see that this was just a small project, though, and that's why you kept it simple. Fair enough. I know what it is to be tired of working on a game. Keep up the nice work. I look forward to whatever you make next :)