Yeah, I also once made some effort into translating crap games.
I dumped the script to Takeshi's Challenge, largely because it's such an infamous crap game.
But I also tried hacking Kagerou Densetsu for Famicom.
An RPG with Zelda II-like fight scenes, with multiple party members.
But also with such features as: Limited healing (I think). Music I can't remember. Demon Sword-level in-controllability (you seen when AVGN played Demon Sword? "What happens you try to [ attack the enemy with your sword ] ?" "YOU DIE!"). Terrible graphics (a game made in 1990 with graphics that would've been just average in 1986. If you play NES, you know that's a pretty big leap in quality.)
The only positive thing is that a site I read suggests a bunch of debug cheats were left in the game.
I got as far as hacking the vertical text routine into horizontal, but it still had some bugs as I recall.
Maybe I'll work on that when I'm more in a mood to torment people with crappy-game patches.