The only major difficulty is getting all fifteen-thousand gems, which can be annoying. If you don't have Sparx's gem-finder ability, which you get from the Sparx level in Midday Gardens, then it can be extremely hard, especially in levels like Lost Fleet. Most others can be simple, though some of the gems in the mission portals can be annoying to find, as well. And yes, there are speedway stages. There are four of them: Mushroom, Country, Honey, and Harbor Speedway. If you have trouble with the speedways in the other games, then that will might be a problem, because they made them more difficult in Year of the Dragon (at least, in the original). However, I never have major trouble with the speedways, and maybe you will stop having those problems. I'm shocked to know you have trouble with Sunny Flight.