For a flappy bird game, this is great! I liked how you used antigravity to make the character fly to be able to avoid the balls, which change velocity too!
Rating:
Design: 4
The design is great but you could've tried to make the art a little better, let's say using pixel art.
Innovation: 4
This game is a flappy bird variant so it isn't that innovative.
Story: 5
As this game is story-less like many others, it would be 5!
Relevance to the theme: 5
The way you used antigravity here was great! The character flying, the balls, everything!
Overall this game is good and could be improved in input, like @40wattstudio mentioned.