Secret Areas are introduced in this new version of lunia, from there you can obtains coins, potions, rare/unique box & puppet npc (penguin, cactus, cannon flower so far) and for every secret you get a little of exp. This guide will show you a screenshot of the entrance to all the secrets per stage (i hope ), see where the char is heading and the map position.
Well, here are 3-4's spots. The arrows might not be so accurate, but just look at the mini map and it won't be hard to figure out. You access secret 3 directly from secret 2's area. Secret 4 is just before the boss (there's a meat chest bellow the entrance).