Nice first game! It was fun to play. But I feel when you lose, you should restart at the current level, not the start of the entire game. Also, it might be good to display the score on the game over screen so you can see how well you did up to that point.

Very good for a first attempt!

Smooth controls and most importantly, it was fun to play :)

If you want pointers I think the biggest improvement  you could make is to adjust the camera.

Make it so jumping does not also move the camera, that way you can avoid the problem of not seeing the ground before you jump down from a higher platform.

Not bad for a first game! Great understanding of the basics, I'm sure you learned a lot making it! Keep up the great work!