THANK YOU!
A battery system was something I was planning on initially. Picking up batteries would stop you dead in your tracks, forcing you to enter a generated WASD combination (theme!) to actually insert the battery and be on your way.
Due to my daytime job taking up more energy than anticipated, I had to downscope however. The (overly) subtle theme interpretation that currently is in place, was very much an afterthought, but hey, it sorta works at least!