My first time was 9:29 I died a couple times at the end. Then I played again and got 6:19.
I liked the game! The boss was very cool but a bit too easy.
The blue-orange colors were too much for me. The green palette was more pleasant to play.
Also I found hard at the beginning to understand what was part of the background. It was common in Gameboy to only use the darker green for stuff that you can interact with (platforms, walls, items, etc) and use only the three other colors in the background.