Enjoyed this very much. The experience felt very authentic to the gameboy, music was excellent and I think the gameplay did a great job of teaching good habits (not over relying on full boost, learning to use the curve of gravity from planets) through game design.
It was unclear to me on the page whether the inversion or change in color palettes that would happen from time to time was a bug. Whether it is intentional or not I would say my only area to suggest improvement would be to remove that. None of the others I saw looked as good as the original if it is intentional, and if it is a bug it was a distracting one. This is a very minor nitpick on a very good game. :)