I personally do not enjoy this type of game, but I appreciate and understand what you're going for. The tough and unforgiving/punishing game like "Getting Over It" which got popular due to youtubers creating videos of them getting very frustrated. A game for sadists if you will.
What I liked about it was that you could actually get good at the controls. With practice you could be rewarded with getting far, but the littlest mistake can send you back to the beginning of the level.
I might suggest another 1 or two easy levels. Perhaps they were easy for you... I gave up when I got to the clouds section of the 2nd stage.
The minor improvement I would work on is the ability to unstuck yourself. I would often end up in an odd angle and the rocket wouldn't budget no matter what I press. I guess it doesn't become a problem if you're good about keeping your ship on its feet.