First of all, thank you for sharing such a fun game.
The graphics and music perfectly capture the feel of the NES era and filled me with a wonderful sense of nostalgia.
At first, I found the game quite difficult because I wasn't good at using the reverse thrust, but after many attempts I gradually improved and managed to clear all four stages. (After the fourth stage, the game seemed to loop back to the beginning, so I assume that means I reached the ending.) It felt very satisfying!
A few things stood out to me while playing. Of course, these are just my personal thoughts on the game design.
I think the game might feel even more exciting if it had a slightly faster pace. The platforming challenges throughout the stages were enjoyable because they encouraged me to think and practice my movement. However, while the enemies made the screen feel more lively, I didn't feel they added much to the gameplay. In my case, I often found it easier to simply take the damage and keep moving. I think it could be even more interesting if the enemies became meaningful obstacles that required the player to engage with them.
I also felt that the pacing slowed down a little because I often had to stand completely still for several seconds to recover my energy. Perhaps the recovery could be faster while standing still, or there could be another way to keep the flow moving.
Finally, I occasionally experienced some odd interactions with the terrain, such as clipping through the ground or getting caught on edges. There may be a few small issues with the landing or collision detection.
Even with those minor points, I really enjoyed the game overall. It's impressive how much you accomplished in such a short time. Great work, and thanks again for sharing it!