maby some helpfull tips
1)make more caracters (only from the pico series)
2)less fireballs
3)hills in the way
4)boost platforms
5)put some stuff like rolling rocks in it that you also have to doge
(if that kind of stuff is already in it I'm just not good in the game ^^)
6)let pico move his body abit when cornering
7)pt holes in the road that you also have to doge or make it posible to jump
(sorry for my bad english I'm dutch )
well I hope you find this usefull if you continiue it will be one of my favorites thats for sure ^^