I love how authentically black box NES this game feels. That jump does take some getting used to.
I feel like the player is called upon to use that jump in tricky situations a little too early in the game; before they're used to it. I also feel like it'd be nice to have some work-around for situations where the player has made a level unwinnable and are forced to kill themselves on a monster to retry. Especially when those situations happen early on, like with a missed box drop.
Then again, I'm talking about matters of fine-tuning in a game that was completed in a 72-hour window. Just the fact that I'm able to nitpick small details is a testament to how solid this game is already.
Good stuff. And now I'm going to go back in and try out that magic code.