Neat idea on paper, but requires a better use of the mechanic being explored. At full health the concept of shooting bullets out of the air is laughable, meaning that the game ends up being a matter of going through the motions till you get to the 20% life area when you actually have the time to track bullets enough to dodge and intercept them. The issue gets flipped once you get into the 5% health point where the game gets so slow that it becomes boring, often times I found myself spitting out 3 or 4 shots before tapping the spacebar just to see if my bullets were going to connect with anything. What this ends up being is a game where you go from impossible task to a ton of fun to tedious boredom in roughly two hits, and that's the problem.
The shooting physics are more than a little wonky due to the game attempting to follow the path of motion with the angle of shots while also shifting along a moving area, which leads to many shots following a far different angle then they should, especially when these shots are fired mid-air.
If I had to offer a suggestion, it'd be to apply the idea of health dependant time to a game less focused on gunplay. Make it a score based game of sorts where you earn more points the higher your health is, and allow the timing of things in normal speed to be more reasonable. Heck, why not implement an active timeslow function in the game that drains as you use it, recovers slowly, and have it double as your armor? If you use your ability and take damage, you get hurt worse than if you hadn't, but using it might allow you to not be hit at all? A push your luck style of game is perfect for such an idea.
Regardless, the game shows promise, but now's the time to take what you've learnt and apply it to a more focused and indepth form. Here's hoping you can make something of it.