Wow! Honestly, I loved your game!
The dive mechanic adds a good "risk and reward" element; The UI was well executed and make clear our remaining jumps using this yellow bar.
My only complaint is about the controls. I personally would prefer DOWN to dive, and SPACE to jump. And you really should consider using WASD for those who can't play using the arrow keys.
Cute pixel art and good choice for musics and sound effects!
Overall, a great game! I'm happy that I found this little gem! Good job!