What a creative take on the classic platformer presented in such a polished, well-thought-out way!
I love the way you made non-conventional features mechanics - such as switching the sun and moon, pausing the game, and more. It made the gameplay experience feel so unique and engaging. You complemented this with really interesting level design, making for some really amazing gameplay. Amazing job!
Not only this, but the graphics are also really good, and the animations are smooth and logical. I love the pixel graphics and the music. From the "Self-made & used stuff" tab, I can see that you made it yourself! That is really amazing, and I think the music and sound effects fit the game perfectly.
I don't have much to say for feedback, since this game seems to be so well-thought out and excelling on all fronts, maybe consider more of a change to the game when it switches from day to night? Perhaps have night owls hooting at night, or quieter music. This might help contribute to diversifying the atmosphere and helping distinguish the change better.
Overall - super fun! I really enjoyed playing this and love your clever interpretation of the theme, and how you were able to turn it into such a logical, cohesive, and enjoyable game.