I completed the game on Hard Mode, it's an interesting and original concept, but the execution has a few flaws that a few tweaks could make the game a lot better. Please bare with me while I explain my thoughts.
The whole point of a platformer is to have responsive controls. The whole concept is to play with that and, to work around it, one has to be a little more cautious and take the probability of failure into account. The issue with that is the implementation of the randomness and the fact that we have to start over any time we mess up.
The issue with the randomness is that it seems as though it's a simply implementation of testing if a random number is less than the percentage of success. This works great in theory but it doesn't make for great gameplay. Consider, at one point I had 90% on crouch and attempted to use it to dodge a bullet, I left plenty of time but it failed on me four times in a row, and rather than thinking that I should have left more margin for error, it just felt cheap. There really isn't any reasonable way to account for a 1/10000 chance. Instead, I'd recommend some form of dynamic probability so it behaves more intuitively even if it isn't actually true randomness. The way this would work is that every time an ability succeeds, the next attempts have a greater chance of failure, and any time it fails, the following attempts have a greater chance of success. This way you can still work out to have the same success/failure rate on average, but help reduce the streaks that just serve to infuriate the player.
Also, there needs to be something to account for mistakes, some of the harder levels took several attempts, but getting all the way to the end and having one of those bad streaks or a bit of poor timing and I'd have to redo the whole level. Maybe implement some sort of check-point or single hit shield upgrade like with the rapid fire gun.
So, yeah, over all, a neat concept, but it needs some fine tuning. I'd love to see a sequel with some of this taken into account.