Wow this game is incredible. don't know where to start. It is like someone took the addictive quality of pac-man and added the well crafted and carefully well thought out level design of super metroid. All of the environmental hazards are in perfect support of the movement constraints on the ghost and the maze puzzles, and there is a good build up and in game tutorial aspect.
The polish of the visuals is very nice and cohesive. The animations and sounds fit in very well. I felt like the timing of the spikes was tuned so that even if I pressed the direction buttons faster the animations played like I had just narrowly escaped death and that was a nice touch. I never get bored of the looping melody, and having just composed a tune thats arguably too busy for my own game, feels like I just got a masterclass playing yours ; ).
I have only made it to the second or third key I think, died a bunch of times, but got a real sense of accomplishment when I found the right traversal strategy to let me pause enough.
I'll agree with others that the game punishes you very harshly for hesitation and that is challenging and also kind of part of the draw. I still haven't reached the point where replaying the same sections got too old though, because the threat of dying doesn't go away, so it became a challenge to 'speed run' through the level again without making unforced errors.
I'm also not someone who does as well with games where you have to be quick with your button pressing or execute long sequences with the right timing (I'm historically a fighting game button masher and game genie junkie), so selfishly I'd like to see more elements which are about the pre-planning strategy and multiple traversal/exploration aspects that I was already seeing so far. Like more Mario and less Super Meat Boy I guess for a cliche analogy. That being said, this is already a perfect version of what it is, so mad kudos to you Mr. Raimondi.