I've just finished this game. It wasn't bad at all, but perhaps a little tough, specially toward the last bit of the game. So, messing a bit, I've found this little code using the built-in virtuanes cheat searcher.
If you want bosses to have only 1HP at the beginning of the fight, open the "cheat support" options and, on the bottom right part ("data write" section), enter the next code:
(to make it work, you need to select "2 bytes" on the "length" area of the cheat support options before entering the code).
Then click on the "write" button and it's done. That way you'll beat any boss (even the final one) with a single hit. There are some boss battles with multiple enemies, in that case keep applying the code for every enemy in battle.
If you want more cheats, such as no random encounters, you can find them at gamehacking.org.