the game is actually enjoyable and fun to play
but of course every game has its own flaws
1) there is some tiny extra pixels in pixelated balls as I noticed (maybe the sprite is still compressed instead of uncompressed ?)
2) the colliding sound is good but I noticed a wind-like element in the marble hitting sound
3) the UI element is actually good but try to avoid skeuomorphism, it can ruin the charm of the game
"skeuomorphism is a texture that has been applied from real world"
4) again about the sound, it does sound really good, but it could be better having a option turning it off or alternating the sound since some people might be sensitive from the marble sound
5) the table texture is good, but again skeuomorphism
other than that the game is actually fun and enjoyable
addressing these points could make the game even more charming
keep developing !