Funpark Secret Door
A lot of people know this but behind the red dragon's tail,
next to the ramp that takes you to the dragon (to the right)
you will see a door and it looks fake but it's not! If you
go into it, you will be taken to the second floor which has nothing but a rope to grind up to the dragons wing. This can be used for a nice combo. Hope this helps.
To do quad backflips, go to suburbs and go to the house that has two blue pools. Go to the water that's coming out of ground slow and try to jump onto water. If you are on the water that's coming out of ground, hold L1 and down arrow or joystick. This trick is a little hard to do, but worth it!