As far as I know, "tasted the bitter fruit of life" is my own invention, from the phrase "the bitter fruit of <foo>". Unfortunately there's little more to the plot of the game: I ran out of time to add content, having to concentrate on mechanics. I would have wanted to write snippets of flavor text that could be found on levels, but what can you do. The game ends on level 50, where you face the people eater (patent pending).
Very true about the ESC key, I have a steady hand and I've never pressed it accidentally, but honestly it should pop up a confirmation box. It's unlikely that I'll add one at this point, already hard at work on the next project :D