The resolution of the background is low because it's simply an enlarged screenshot which is a huge time-saver, but the best part is the character sprites are reusable. Every pose and expression can be interchanged, plus they're made with vectors so if I need to move an arm I only have to draw a new arm. (There are a few unique poses to keep the characters from feeling static.) Many of the scenes just had to be assembled and that was the biggest boost to production.
Mixing resolutions caused some interesting issues, like what to do when hi-rez characters interact with low-rez stuff. These parts didn't fare so well. There's also the fun fact of Juni's power-ups being just as big as she is. At this scale it becomes comical. I guess the more I analyze it the less appealing it looks for future projects, but the economy of effort versus quality is too good to ignore.