Thank you so much for the awesome feedback! You're absolutely right about the physics, sometimes I ask myself the same question and never get an answer either, but I’ll definitely take another look!
As for the optimal score, things really start to get serious after 9,500 points. My personal record is 12,964, and I definitely see room for improvement! If you're curious, I've listed the merge values on the game's page if you want to check them out for a bit of strategy