Well, it IS hard. And in the beginning you really haven't much.. but you find a lot of stuff, get more life energy, find scrolls to better your primary weapon until it reaches (charged) over the whole screen, learn doublejump and get a lot of secondary weapons and an armor. For now (dunno how far you are, though):
Mushrooms and other ground enemies like the frogs: hit, run back or jump over them and hit again. Important: Don't stay where you are.
Parrots: Driving you nuts the first times but are really easy when you know their timing. Jump towards them and don't wait until they come to you.
On the other side... if you have problems with the normal enemies, you will get very frustrated by the bosses, especially Hume. He is a sucker, but the fascinating thing is, that after I beat the game and played it again, I killed him without loosing energy at all, so this game really is about how good you are with the controls and with seeing the tactics of the bosses.
Edit: btw, I made savegames before and after most of the bosses (~30 savegames in total), if somebody want to play it again and want to start in the middle or so...