Hi there! There aren't any cheats that I know of, I'm afraid. But I can tell you what a D-Counter and a D-Ratio is.
If you've only played the game once, I don't imagine you've gotten too far yet, so you won't need to worry about the D-counter for a while. The D-Counter activates a lil later in the game and starts at 0%. Basically, when you use dragon abilities it goes up. It also goes up on it's only very slowly, but it goes so slow you won't need to worry about that. When it reaches 100% it's game over, so the whole idea of it is to stop you from using your dragon abilities often. Your dragon form in this game is so powerful the game would be easy if you could use it freely.

You've probably heard of the D-ratio in the game already, Ryu's d-ratio at the start of the game is 1/ something in the 8000's. (I can't really remember) The D-ratio is like a status thing in the underground world the characters live in, the lower your D-ratio, the more important you are. You can access secret areas with a low D-ratio.

To lower your D-ratio you have to first complete the game, the better you've done at the game, the lower the d-ratio you will get, then you can restart the game and play through accessing new areas. There are some things you need to do to get the best D-ratio and I know there is a list floating round the forum here somewhere... But basically, you have to have the lowest D-counter possible, save not many times and... Well, I can't remember any more.

As for avoiding the monsters, it's probably better for fighting them because you'll need to level up to get further in the game. But if you're low on health or something, you can distract them by using Fresh Meat, which you throw at them and then run past while they are busy.

I hope that has helped you.