I wonder how complicated it is to do DOS hacking. I know nothing about it.
It really depends on the game. This one made some things comparatively easy, as it had an English font already built in, and the Korean text was fairly accessibly stored in an old standard format.
Graphics hacking has been the hardest part, the tile viewers used for ROM hacks of console games are mostly useless here. I had to write two converters for graphics myself, and there are still a few things I have no hope finding without assembler hacking, which I'm incapable of. These two bits will most likely remain untranslated in the release:

Left: "Miss" notification above the character in white; Right: Analyze spell enemy status information