Hey, thanks for checking it out! Apologies for the late reply, I thought I responded earlier, oops.
I'm glad the gamepad worked decently, I believe the LB and RB were also bound to the Joystick buttons, which is still awkward to press but it may have been a bit easier than combining LB+LT or RB+RT, haha.
The physics is luckily mostly handled by UE4. We had to deal with some minor vector math to make sure the torque direction was correct, and allowing the ball to roll along wood was definitely a challenge, but the hardest part was making sure it was done in an enjoyable way. We went through a few different versions of characters before settling with the sphere-cube-spikes-thrust combination.
The original character was actually several spheres all constrained to one another with a main mesh overlapping them all to create the effect of a gooey sort of mass. It was definitely a very fun jam :D