1. The game ran fine on my desktop. The graphics are nice, it looks like a real wood table, even the ball can be seen moving behind the hole when it falls down.
2. The difficulty was hard. At first it's impossible but with patience I got to level 3, hole 18/19 on easy.
3. Physics seemed fine to me, the ball moves as expected and felt like it carried its velocity accurately.
4. I think its a good game, you could add a reward system for completing each level. Maybe an easier level but with two balls starting in opposite sides?