Yes! it does do the math for Magnus effect. Source code is all client side you can take a look at it.

But early on when I started this, I prompted the LLMs strongly to focus on having accurate real world physics baked in.

Nice! Why I can only select the angle in multiples of 5°? I expected to be able to rotate the blade just a little.

For "Back Spin" I used: angle = open 50°, Brush = -20° down, Speed = 13 km/h and I got a success "Lands - Smash Food". Do you have a table of the possible classification?