Some tips, cheats
The main cheat I have to offer is how the passcode system works. You have two numbers, separated by a dash. The first number tells you how many potions and weapons you have and also how much gold. The second number tells you how much health you have, what screen you are in, and what magic spells you have. The best way to explain it is by example.
For the first number of the passcode,
123400093 TIMES 7 = 863800651
So, if the first number of your passcode is 863800651, this means that you have 1 small potion, 2 medium potions, 3 large potions, 4 weapons, and 93 gold, as you can see by looking at the number on the left. Note the multiplication by 7. The gold must be a five digit number and the other numbers should be single digit.
For the second number of the passcode,
381915 TIMES 307 = 117252817
So if the second number of your passcode is 117252817, then you have 38 health, are in screen 19, and have "15" for your spells. The explanation of "15" has to do with binary numbers, but instead of explaining that I'll just say if your spell # is
01 -- you have 1 spell
03 -- 2 spells
07 -- 3 spells
15 -- 4 spells
31 -- 5 spells
63 -- 6 spells
So in this case you have 4 spells. Note the multiplication by 307 this time instead of 7.
I also have some tips. Tip 1: Run quickly past all monsters except bosses instead of fighting them. You lose less health this way. Tip 2: If you decide to get money the fair way instead of by cheating, you can get money fastest by killing green blobs--lure 4 of them to attack you, and then you can dodge their bounces and hit them when they land.
I also have a problem. How the hell do I open up that top chamber after killing the red ninjas in the battlemage fortress? It just stays locked. Of course I could transport myself into the locked region using a passcode, but I'd rather follow the plot of the game.