I assume you are playing a translated rom, because it gives you the clues necessary to get the equipment that allows you to beat the game. If not, then I don't really see how you can figure out the secrets needed to beat the game other than pure trial-and-error, or a guide.
That the PCE version allows you to up your speed stats, or health, almost instantly, it is extremely more user-friendly than the arcade original, which I have never been able to get further than floors 15-18 (out of 60!). It is probably one of my favorite PCE games (at least translated!).
Getting a feel for the game can be a little tricky. You don't just hit the attack button like zelda; you need to press and hold the button to attack monsters. You need to rush back and forth with the attack button held against armored enemies to win the jousting match with them and not die. You need to be aware of which direction your shield is facing so you can deal with wizards - with sword down, it's right in front of you, but when your sword is held your left or right can be exposed depending on where you face. All of this is pretty involved for a mid-80s release. To say nothing of intelligently using the pickax to break down walls, discovering the right equipment.
I can't reiterate how important it is to find out nearly all of the secrets (some are red herrings or traps - usually the clues in the PCE port will give you a hint to not pick something up in a particular floor, IIRC). They are your ticket to the top.