This is so much fun! My highest score was 6900, (unintentionally).
I found some advanced tricks you can do to make the most of the dice.
The first thing is using bullets form a dice that has another die falling onto it, if you jump to the side and use all the bullets, the dice will still stack on top. This can get the most out of the bullets.
Another tip is if you are on top of a die that is falling, you can use the bullets on the lower side, meaning if timed correctly, you can shoot way more bullets without breaking the die.
Edit: Also, I was able to fall out of the map.