On phone so this will be a rough reply.

The Chaos Emerald stages work like this: Collect rings to increase your time. Collect blue spheres to gradually increase speed level. The track is a loop like a race car track. So collect both while avoiding obstacles and you'll eventually catch up to the UFO. When you get close enough you'll automatically collect it.

There is a point to the blue sphere mini games. Get all the rings and clear the stages to unlock stuff.

That boss may seem annoying at first, but all you have to do is hit one of the fat, blue missiles. You can even roll into it. Just avoid the red missiles. Depending on the arc, your jump does get affected, but you can easily time it so that you can jump when the surface is flat, so your jumps aren't messed with. In between most segments you can get more rings, so that makes the boss easy to deal with too. I like the boss because it uses speed as a theme which is usually reserved for end game stuff or special bosses.