You have to go to the room in the Labyrinth that has the guy that uncurses you. He will transform you back to regular Pit. You can see the maps (if you want) at gamefaqs.
http://www.gamefaqs.com/nes/587380-kid-icarus/faqs
Also try to get as many points as you can in each level as that will increase your "health meter". It's tough at first, but with more health it becomes easier especially if you buy some water of life to refill your hit points. With a barrel you can hold up to 8 bottles. A feather is handy if you happen to fall.
Make sure you power up your weapon as well. It's very useful.
I cleared it on my 3DS (the VC version) a few months ago.
starcraft: "I and every PS3 fanboy alive are waiting for Versus more than FFXIII.
Me since the games were revealed, the fanboys since E3." 
Skeeuk: "playstation 3 is the ultimate in gaming acceleration"
