Well you start out walking around the over world doing tasks, advancing through the story, and then you spend a lot of time going around the wave world were you can walk on wave roads, and randomly run into battles in which case you use your buster and battle cards to defeat viruses. And in order to switch between the two ( For the first two games ) you have to find wave holes. I can get you a boss battle if you want to show you how battles work.
Legends is awesome - it really shows the life of megaman xD Is megaman good on the DS? I've always wanted to get one, but I'm not sure it's going to be good
If you have ten bucks and a wii you should download Megaman 9. Its a new came made to look old. But the X series is also awesome, its how I started playing megaman in the first place.