It's an interested idea that provides a challenge compared to the old flappy bird game. However, sometimes when you restart gameplay, the first barrier spawn so high or low that the bird doesn't have enough time to avoid them yet resulting in a easy game over.

The design for the bird and gems look nice. The bird being upside down and the text being reversed and upside down definetely attention grabbing. 

Collision needs work as the gem does not get collected until the bird is about halfway inside the gem.  Also, a gem spawned with half of it overlapping with a pipe.