It took me a while but I got to the end. The end battle is too easy IMO, at least it's easier than the robot with shield. At the end credits I only got 2 secret, so I try to reload checkpoint. When I tried it, I keep dying and I can't do anything (not even go to pause menu).
Also another suggestion, It'll be great if I can continue from where I was. It's a pain to try to go back to where I was before.
It was fun to play it, and some puzzle solution is hard to figure out but it's not impossible. I love it.