Obviously the beta testers were of no use for you as the game is unplayable.
It is a good idea to also test a game yourself before publishing it. Some bugs I found:
Third throw has no clicking prompt to begin.
The first arrow for the third dart sometimes never move in to the dart board.
Sometimes you score the same as a previous throw even if it is obvious that you miss the board.
The game lags more and runs slower the longer into the game you play. This creates dead spots on the board as bars jump between the same spots and a throw cannot be registered until the next frame. I have for example not been able to hit 5 or 19 close to end game. The pace is not consistent so it can suddenly speed up and then slow down making you miss what you aim at. If you finish the game and start a new it actually resets to normal as if you just closed and opened the game again.
Sometimes The score I have left to finish gets higher instead of lower, and this seems to happen at random and by any score. This has nothing to do with getting bust.
Sometimes, usually close to end game, the score resets to what it was before my three throws as if I get bust, but it usually happens when I score way less than what I have left.
Sometimes the number that shows what you just hit changes just after the throw. It is usually to something that is next to that value on the board, but I have seen 5 change to 15 and I hit 15, not tripple 5. They are not close to each other.
Double top and Mad House medals do not work.